Front-loading syringe adapted to releasably engage a medical injector regardless of the orientation of the syringe with respect to the injector

ABSTRACT

A syringe for use with an injector includes a body having a rear end and a front end, a plunger movably disposed within the body, an attachment member associated with the body and adapted to releasably engage a syringe retaining mechanism of the injector regardless of the orientation of the syringe with respect to the injector, and an encoding device operable to provide syringe information to the injector.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a division of application Ser. No.09/777,020, filed on Feb. 5, 2001, which is a continuation-in-part ofapplication Ser. No. 09/718,230, filed on Nov. 21, 2000, now abandoned,and claims priority to Provisional Application Serial No. 60/180,647,filed on Feb. 7, 2000, and to Provisional Application Serial No.60/229,550, filed on Sep. 5, 2000.

BACKGROUND OF THE INVENTION

[0002] This invention relates to medical injectors, and syringes,syringe interfaces, syringe adapters and syringe plungers for usetherewith. More particularly, the present invention relates tofront-loading medical injectors, and syringes, syringe interfaces,syringe plungers and adapters for use with new or existing medicalinjectors wherein a syringe of special construction is mountable uponand removable from the injectors by a releasable mechanism.

[0003] Medical injectors and syringes for injecting contrast media intoa patient for imaging biological structures are known in the art. Forexample, U.S. Pat. No. 4,677,980, issued to D. M. Reilly et al. on Jul.7, 1987, and entitled “Angiographic Injector and Angiographic Syringefor Use Therewith,” which is assigned to the same Assignee as thesubject application, discloses an angiographic injector apparatus. Theapparatus is designed for injecting contrast media into the vascularsystem of an animal, in which syringes are rear-loaded into a pressurejacket of the injector. More specifically, the apparatus comprises arotatable turret which carries a pair of the pressure jackets and whichis rotatable so that when one of the pressure jackets, into which asyringe has been rear-loaded, is in an injection position, the otherpressure jacket is in a position in which an associated syringe can berear-loaded. Subsequently, when injection of contrast media from thefirst syringe is completed, the turret is rotated to move the firstsyringe to an unloading-loading position, with the second pressurejacket and the syringe concurrently being moved into the injectionposition.

[0004] In the apparatus disclosed in the '980 patent, a drive member ofthe angiographic injector can be drivingly connected to, or disconnectedfrom, a plunger of a syringe at any point along the path of travel ofthe syringe plunger by a releasable mechanism. However, for thereleasable mechanism to correctly operate, the syringe plunger must beproperly oriented to mate with the injector piston. Further, duringloading of the syringe on the injector, the syringe must be correctlyaligned within a respective pressure jacket to allow the syringe plungerand the injector piston to connect to and disconnect from each other.

[0005] An improved apparatus over the '980 patent apparatus is disclosedin U.S. Pat. No. 5,383,858, issued to D. M. Reilly et al. on Jan. 24,1995, and entitled “Front-Loading Medical Injector and Syringe for UseTherewith,” which is also assigned to the same Assignee as the presentapplication. In the apparatus described in the '858 patent, the syringeis front-loaded onto, in at least one embodiment, a pressure jacket-lessinjector, overcoming one of the drawbacks of the '980 patent injectorapparatus.

[0006] The injector described in the '858 patent has a first releasemechanism for attaching and releasing the syringe from the injector. Inaddition, the apparatus includes a second release mechanism that engagesand disengages the injector piston from the syringe plunger. Uponrotation of the syringe, the syringe is attached to or released from theinjector and, simultaneously, the plunger is attached to or releasedfrom the piston. The structure disclosed requires that the syringe beinstalled on the injector in a specific orientation so that the syringecan releasably engage the injector and, simultaneously, the plunger canreleasably engage the piston. In addition, as with the syringe disclosedin the '980 patent, during assembly the syringe plunger must becorrectly oriented within the syringe.

[0007] Another injector apparatus is disclosed in U.S. Pat. No.5,300,031, issued to C. Neer et al. on Apr. 5, 1994, and entitled“Apparatus for Injecting Fluid into Animals and Disposable FrontLoadable Syringe Therefor.” The '031 patent discloses variousembodiments of a pressure-jacketed injector wherein a syringe is loadedinto and removed from an injector pressure jacket through an openingprovided in the front end of the pressure jacket. To retain the syringewithin the pressure jacket, for example, during an injection operation,the front end of the syringe is locked to the front end of the pressurejacket. To correctly connect the syringe to the pressure jacket, thesyringe may only be inserted into the pressure jacket in oneorientation.

[0008] In each example discussed above, the syringe must be connected tothe injector in a specific orientation to assure proper syringemounting. Proper alignment is required to assure that the syringe may beoperated properly during a medical imaging procedure. The requiredorientation, however, hinders rapid attachment and replacement of thesyringe. The required orientation may also increase the manufacturingassembly cost and complexity of the syringe.

[0009] Accordingly, while the above injector and syringe apparatuseshave proven effective, a need has arisen for a simpler front-loadingmedical injector. More specifically, to facilitate further the loadingoperation, a need has arisen for a syringe that can be easily connectedto the injector without regard for the specific orientation of thesyringe and/or syringe plunger. In addition, to simplify assembly of thesyringe components, a need has arisen for a syringe with a plunger thatdoes not need to be oriented in a specific relation to the barrel orbase of the syringe. Furthermore, to minimize the time required toprepare an injector for an injection procedure, a need has arisen forinjectors providing automated features.

SUMMARY OF THE INVENTION

[0010] The present invention provides medical injectors, syringeinterfaces, syringe adapters, syringe plungers and syringes for usetherewith which address the needs that have arisen for a simplerinjector and syringe system. Specifically, the present inventionprovides, in one aspect, a syringe interface and a mating syringe thatcooperate to allow the syringe to be easily, readily and securelyfastened to a medical injector. The syringe need not be oriented in anyparticular manner before being connected to the injector. In addition,the plunger need not be oriented in any particular manner with respectto the barrel of the syringe. The syringe and plunger both are providedwith release mechanisms so that the syringe can be quickly installed onand unloaded from the injector and replaced with a new syringe.

[0011] To accomplish these objectives, the present invention provides asyringe for engaging an injector. In a preferred embodiment, the syringeincludes a syringe body having a syringe forward end adapted to dispensefluid and a syringe rearward end adapted to engage with the injector. Aplunger or plunger cover is axially reciprocable within the syringebody. A flange member is disposed at the syringe rearward end. Theflange is adapted to engage a flexible ring within a connector mechanismon the injector housing, or on a syringe interface or an adapterconnected to the injector housing. The flange and flex ring combinationprovide for engagement of the syringe to and release of the syringe fromthe injector. Further, the syringe includes one or more members forengaging the flexible ring to permit disengagement of the syringetherefrom.

[0012] In an alternate embodiment, the flange member may be disposed atthe syringe forward end and the flexible ring may be disposed on aforward end of a pressure jacket connected to an injector.

[0013] In another embodiment, the syringe includes a syringe body havinga syringe forward end adapted to dispense fluid and a syringe rearwardend adapted to engage with the injector. A plunger or plunger cover isaxially reciprocable within the syringe body. At least one tab or flangemember (which may be resilient) is disposed at the syringe rearward end.The at least one tab or flange is adapted to engage a wall portion on aninjector, or a syringe interface or an adapter connected to theinjector, when the syringe engages with the injector. The at least onetab or flange provides for engagement of the syringe to and release ofthe syringe from the injector.

[0014] In still another embodiment, the syringe includes a syringe bodyhaving a syringe forward end adapted to dispense fluid and a syringerearward end adapted to engage with the injector. A plunger is axiallyreciprocable within the syringe body. At least one resilient tab isdisposed at the syringe rearward end. The at least one resilient tab isadapted to engage a wall portion on the injector, or a syringe interfaceor an adapter connected to the injector, when the syringe engages withthe injector. The at least one tab provides for engagement of thesyringe to and release of the syringe from the injector.

[0015] In an alternate embodiment, the syringe includes at least tworesilient tabs adapted to engage the wall portion of the injector whenthe syringe engages the injector. In still another embodiment, thesyringe includes more than two tabs that are arranged around its base sothat the syringe securely engages the injector.

[0016] The present invention further provides an injector systemcombining a syringe and an injector. The syringes have the same generalconstructions as described above. The injector includes an interfaceadapted to receive the rearward end of the syringe. In a preferredembodiment, the interface of the injector includes a flexible ring forengaging a flange member disposed on the syringe. In an alternateembodiment, the flexible ring may be disposed on a forward end of apressure jacket connected to the injector, and the flange member may bedisposed on the forward end of the syringe to engage the flexible ring.

[0017] In another embodiment, the injector includes a forward portionhaving a first diameter adapted to receive the syringe rearward end. Theinjector interface also includes a rearward portion having a seconddiameter, larger than the first diameter, and a ledge disposed betweenthe forward portion and the rearward portion, joining the forwardportion and the rearward portion together. The at least one tab on thesyringe is adapted to resiliently engage the ledge when the syringe isengaged with the injector. The interface of the injector furtherincludes a collar, reciprocable within the rearward portion adjacent awall therein, adapted to urge the at least one tab inwardly to disengagethe at least one tab from the ledge, thereby enabling removal of thesyringe from the injector.

[0018] The present invention further provides an injector piston, asyringe plunger assembly and a combined piston/plunger assembly. In apreferred embodiment, the syringe plunger assembly includes a plungercover and an associated plunger cover support ring disposed within thesyringe. In an alternate embodiment, the syringe plunger assemblyincludes only a plunger cover disposed within the syringe. The injectorpiston is preferably shaped to complement the shape of the plungercover. In addition, the injector piston is preferably adapted to pushthe syringe plunger cover during forward axial movement, without anactual connection being made therebetween. During retraction of theplunger, however, the injector piston is adapter to connectively engagethe plunger or plunger cover.

[0019] In one embodiment, the piston/plunger assembly includes a pistonassociated with an injector, a piston sleeve surrounding the piston, acollar connected to one end of the piston sleeve, the collar defining anopening through which the piston extends, a plunger cap connected to thecollar, the plunger cap defining an interior space, a gripper extenderdisposed on an end of the piston within the interior space of theplunger cap, a plurality of slots through a side of the plunger cap, aplurality of grippers disposed through the slots and being engageablewith the gripper extender, and a biasing member in contact with thepiston sleeve. Upon movement of the piston in a direction, the biasingmember biases movement of the piston sleeve to restrict movement in thesame direction to cause the gripper extender to push the plurality ofgrippers through the slots in the plunger cap for engagement with aplunger or rubber cover within a syringe.

[0020] In other embodiments, the plunger and piston may be adapted toconnect together electromechanically or electromagnetically.

[0021] Further in accordance with the embodiments set forth above, thepresent invention also provides an adapter for receiving a syringe. Theadapter engages with an injector and is disposed between the injectorand the syringe. The adapter includes an adapter forward end adapted toengage the syringe. In one embodiment, the adapter rearward end has atleast one resilient tab that is adapted to engage with the injector.

[0022] The present invention further provides for an adapter assembly.The adapter assembly includes an adapter and a syringe for usetherewith. In a preferred embodiment, the adapter includes an adapterrearward end comprising a flange member adapted to engage with aflexible ring of an injector. In this embodiment, the adapter wouldallow an injector designed according to the present invention to acceptconventional syringes.

[0023] In an alternate embodiment, the adapter may have a rearward endincluding a mechanism allowing it to mate with existing injectors (suchas the injectors disclosed in U.S. Pat. Nos. 4,677,980, 5,383,858 and5,300,031, the disclosures of which are hereby incorporated byreference) and a forward end including a flexible ring or a ledge orshoulder member allowing it to mate with syringes designed according tothe present invention. In this embodiment, the adapter would allowconventional or existing injectors to accept syringes designed accordingto the present invention.

[0024] In addition, the present invention provides methods for engagingor installing the front-loading syringes and adapters of the presentinvention and/or existing syringes with the front-loading injectors ofthe present invention and/or existing injectors

[0025] Furthermore, the present invention provides injectors andinjector systems having certain automated features that facilitate thepreparation thereof for injection procedures.

[0026] The present invention offers many advantages over the prior art.For example, the present invention provides a syringe that does not haveto be aligned and/or oriented with respect to an injector forinstallation thereon. Further, the present invention provides a syringein which alignment, either radially or axially, between the plunger andsyringe is not required.

[0027] Moreover, the piston of the present invention may be designed sothat it does not permanently engage the plunger. So designed, theplunger acts primarily as a pusher during the injection operation. Onlywhen the plunger must be retracted, for example, to aspirate fluid intothe syringe, may an engagement mechanism be activated so that the pistonconnects to the plunger. By virtue of this arrangement, the plunger maybe left in any position when the syringe is removed from the injectorsystem.

[0028] The present invention, along with the attributes and attendantadvantages thereof, will best be appreciated and understood in view ofthe following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The various embodiments of the present invention are described inconnection with the figures appended hereto, in which:

[0030]FIG. 1 is a perspective view of an injector apparatus inaccordance with the present invention, showing an injector housing and asyringe in a disassembled relationship;

[0031]FIG. 2 is an enlarged perspective view of the syringe illustratedin FIG. 1, shown connected to a front wall of the injector housing,illustrating how a flange disposed at a rearward end of the syringe mayprevent leaking fluid from entering the injector housing;

[0032]FIG. 3 is an enlarged cross-sectional view of the syringe shown inFIGS. 1 and 2, illustrating the construction of a forward end of thesyringe;

[0033]FIG. 4 is a perspective view of another embodiment of the presentinvention, illustrating a syringe and a pressure-jacketed injector in adisassembled relationship;

[0034]FIG. 5 is another perspective view of the embodiment illustratedin FIG. 4, showing a piston displaced at a more forward position thanthat illustrated in FIG. 4;

[0035]FIG. 6 is a cross-sectional view of the syringe and housingillustrated in FIGS. 1 and 2, showing the secure connection of thesyringe to the front wall of the injector housing through tabs attachedat the rearward end of the syringe;

[0036]FIG. 7 is an enlarged cross-sectional view of the structuresenclosed by circle VII in FIG. 6, showing in greater detail theconnection of the syringe to the front wall of the injector housing;

[0037]FIG. 8 is an enlarged perspective view of the tabs illustrated inFIG. 7 that are connected to the rearward end of the syringe illustratedin FIG. 1;

[0038]FIG. 9 is an enlarged cross-section of an alternate embodiment oftabs attached at the rearward end of a syringe for engagement with afront wall of an injector, showing essentially the same structuresillustrated in FIG. 7;

[0039]FIG. 10 is an enlarged perspective view of yet another embodimentof a syringe in accordance with the present invention, illustrating atleast one tab at a base of the syringe for engagement with a ledgedefined in an interface of an injector housing;

[0040]FIG. 11 is an enlarged perspective view of the syringe illustratedin FIG. 10, showing the at least one tab from the rearward end (or baseside) of the syringe;

[0041]FIG. 12 is an enlarged perspective view of another embodiment of asyringe in accordance with the teachings of the present invention,illustrating two tabs at the base of the syringe for engagement with theinjector housing;

[0042]FIG. 13 is an enlarged perspective view of the syringe shown inFIG. 12, illustrating the two tabs at the rearward end of the syringe;

[0043]FIG. 14 is an enlarged perspective view of still anotherembodiment of a syringe in accordance with the present invention,illustrating more than two tabs at a base of the syringe for engagementwith an injector housing;

[0044]FIG. 15 is an enlarged perspective view of the syringe illustratedin FIG. 14, showing the base end of the syringe with the plurality oftabs;

[0045]FIG. 16 is a partial, enlarged perspective view of an alternateembodiment of the tab arrangement illustrated in FIGS. 1 and 8;

[0046]FIG. 17 is a cross-sectional view of the tab arrangementillustrated in FIG. 16, taken along line XVII-XVII;

[0047]FIG. 18 is a cross-sectional view of the syringe illustrated inFIGS. 14 and 15 with a portion of a front wall of an injector housing,showing a ledge that is securely engaged by tabs at the base of thesyringe, and also showing a reciprocating collar that disengages thetabs from the ledge;

[0048]FIG. 19 is a cross-sectional illustration of the embodimentillustrated in FIG. 18, showing the tabs engaging the ledge so that thesyringe securely engages the injector housing;

[0049]FIG. 20 is a cross-sectional illustration of the embodiment shownin FIGS. 18 and 19, showing the engagement of the reciprocating collarwith the tabs to disengage them from the ledge of the injector housing;

[0050]FIG. 21 is a cross-sectional view of an adapter assembly connectedto the syringe illustrated in FIGS. 14 and 15;

[0051]FIG. 22 is a cross-sectional view of an alternate embodiment ofthe adapter assembly illustrated in FIG. 21, where the adapter includesa tabbed opening for engagement with the injector housing;

[0052]FIG. 23 is a perspective view of the adapter and syringeillustrated in FIG. 22;

[0053]FIG. 24 is another perspective view of the adapter and syringeillustrated in FIG. 22;

[0054]FIG. 25 is a cross-sectional view of an embodiment of a plungerand piston according to the teachings of the present invention, showingan electromagnetic mechanism that causes the plunger and piston to beattracted to one another during operation of the apparatus;

[0055]FIG. 26 is a partial cross-sectional view of another embodiment ofa plunger and piston, showing an electromechanical mechanism that causesthe plunger and piston to be releasably attached to one another duringoperation of the apparatus;

[0056]FIG. 27 is an enlarged cross-sectional view of the piston andplunger illustrated in FIG. 26, showing the piston engaging the plunger;

[0057]FIG. 28 is a cross-sectional view of the combination of the pistonand the plunger shown in FIG. 27, the view taken along lineXXVIII-XXVIII, showing two protrusions extended so that the pistonengages the plunger;

[0058]FIG. 29 is a cross-sectional view of the combination of the pistonand the plunger shown in FIGS. 26-28, with the two protrusions retractedso that the piston can disengage from the plunger;

[0059]FIG. 30 is an enlarged cross-sectional view of a plunger accordingto the teachings of the present invention, illustrating the placement ofa pressure-sensing device in the plunger;

[0060]FIG. 31 is an enlarged cross-sectional view of the plungerillustrated in FIG. 30, showing the plunger subjected to a pressure fromthe fluid contained in a syringe (not illustrated);

[0061]FIG. 32 is a side view illustration of an alternate embodiment ofthe present invention where tabs are added to a syringe cap that engagesthe end of a pressure jacket;

[0062]FIG. 33 is an enlarged cross-sectional view of an alternateembodiment of the apparatus shown in FIG. 7;

[0063]FIG. 34 is an enlarged cross-sectional view of the alternateembodiment of the apparatus shown in FIG. 33;

[0064]FIG. 35 is a side view illustration of another embodiment of theapparatus that releasably connects the plunger and piston to oneanother;

[0065]FIG. 36 is a side view illustration of still another embodiment ofthe apparatus that releasably connects the plunger and piston to oneanother;

[0066]FIG. 37 is an end view illustration of the separable members shownin FIG. 36;

[0067]FIG. 38 is a perspective cut-away illustration of a pressurejacket embodiment of the present invention showing the reciprocatingcollar disposed within the pressure jacket;

[0068]FIG. 39 is a cross-sectional view of the pressure jacketembodiment illustrated in FIG. 38, taken along line XXXIX-XXXIX;

[0069]FIG. 40A is an exploded, perspective view of another embodiment ofa front-loading syringe interface and syringe system in accordance withthe present invention;

[0070]FIG. 40B is a perspective view of the system shown in FIG. 40A inan installed position;

[0071]FIG. 40C is a perspective view of the syringe interface shown inFIG. 40A in an open position;

[0072]FIG. 41A is an assembled, perspective view of another embodimentof a front-loading syringe interface and syringe system in accordancewith the present invention;

[0073]FIG. 41B is a perspective view of the system shown in FIG. 41A inan open position;

[0074]FIG. 41C is a front, perspective view of the syringe interfaceshown in FIG. 41A in an open position;

[0075]FIG. 41D is a rear, perspective view of the syringe interfaceshown in FIG. 41A in an open position;

[0076]FIG. 42A is an assembled, perspective view of an alternateembodiment of the embodiment of the front-loading syringe interface andsyringe system shown in FIGS. 41A-41D;

[0077]FIG. 42B is a perspective view of the system shown in FIG. 42A ina disengaged position;

[0078]FIG. 42C is a front, perspective view of the syringe interfaceshown in FIG. 42A in a closed position;

[0079]FIG. 42D is a plan, perspective view of the syringe interfaceshown in FIG. 42A in a closed position;

[0080]FIG. 43A is an exploded, perspective view of another alternateembodiment of the embodiment of the front-loading syringe interface andsyringe system shown in FIGS. 41A-41D;

[0081]FIG. 43B is a perspective view of the syringe interface shown inFIG. 43A in a closed position;

[0082]FIG. 43C is a side, perspective view of the system shown in FIG.43A in a first disengaged position;

[0083]FIG. 43D is a perspective view of the system shown in FIG. 43A inan installed position;

[0084]FIG. 43E is a perspective view of the system shown in FIG. 43A ina second disengaged position;

[0085]FIG. 43F is a perspective view of the system shown in FIG. 43A inan open position for syringe removal;

[0086]FIG. 43G is an exploded, perspective view of the system shown inFIG. 43A with the syringe interface in an open position;

[0087]FIG. 43H is a front, perspective view of the syringe interfaceshown in FIG. 43A in an open position;

[0088]FIG. 43I is a rear, perspective view of the syringe interfaceshown in FIG. 43A in an open position;

[0089]FIG. 44A is a perspective view of a slightly altered version ofthe syringe interface shown in FIGS. 43A-43I incorporated in or mountedon an injector head;

[0090]FIG. 44B is a rear, perspective view of the syringe interface andinjector head shown in FIG. 44A;

[0091]FIG. 45A is a perspective view of a second, slightly alteredversion of the syringe interface shown in FIGS. 43A-43I incorporated inor mounted on an injector head;

[0092]FIG. 45B is a rear, perspective view of the syringe interface andinjector head shown in FIG. 45A;

[0093]FIG. 46A is an exploded, perspective view of a first preferredembodiment of a front-loading syringe interface and syringe system inaccordance with the present invention;

[0094]FIG. 46B is an assembled, perspective view of the syringeinterface shown in FIG. 46A;

[0095]FIG. 46C is a perspective view of the system shown in FIG. 46A ina disengaged position;

[0096]FIG. 46D is a perspective view of the system shown in FIG. 46A inan installed position;

[0097]FIG. 47A is a perspective view of an alternate embodiment of thefirst preferred embodiment of the front-loading syringe interface andsyringe system shown in FIGS. 46A-46D in an installed position;

[0098]FIG. 47B is a perspective view of the system shown in FIG. 47A ina disengaged position;

[0099]FIG. 47C is an exploded, perspective view of the system shown inFIG. 47A;

[0100]FIG. 47D is an exploded, perspective view of the syringe interfaceshown in FIG. 47A;

[0101]FIG. 47E is a rear, partially assembled, perspective view of thesyringe interface shown in FIG. 47A;

[0102]FIG. 47F is a rear, exploded, perspective view of the syringeinterface shown in FIG. 47A;

[0103]FIG. 48A is an exploded, perspective view of still anotherembodiment of a front-loading syringe interface and syringe system inaccordance with the present invention;

[0104]FIG. 48B is a perspective view of the system shown in FIG. 48A ina disengaged position;

[0105]FIG. 48C is a perspective view of the system shown in FIG. 48A inan installed position;

[0106]FIG. 49A is an assembled, perspective view of another embodimentof an injector piston and syringe plunger interface system of thepresent invention;

[0107]FIG. 49B is an exploded perspective view of the piston/plungersystem shown in FIG. 49A;

[0108]FIG. 49C is a perspective view of the piston/plunger system shownin FIG. 49B with the plunger base separated from the plunger cover andassociated with the piston;

[0109]FIG. 49D is a perspective of the piston/plunger system shown inFIG. 49B with the plunger, including the plunger base and the plungercover, separated from the piston;

[0110]FIG. 49E is a rear, perspective view of the piston/plunger systemshown in FIG. 49A in a disengaged position;

[0111]FIG. 49F is an exploded, perspective view of the plunger base andthe plunger cover shown in FIGS. 49C and 49D;

[0112]FIG. 50A is an exploded, perspective view of another embodiment ofan injector piston and syringe plunger interface system of the presentinvention;

[0113]FIG. 50B is an enlarged view, partially in cross-section, of theplunger base and the piston shown in FIG. 50A in an engaged position;

[0114]FIG. 51A is an exploded, perspective view of an alternateembodiment of the injector piston and syringe plunger interface systemshown in FIGS. 50A and 50B;

[0115]FIG. 51B is a perspective view of the piston/plunger system shownin FIG. 51A with the plunger base separated from the plunger cover andassociated with the piston;

[0116]FIG. 51C is an enlarged view, partially in cross-section, of theplunger base and the piston shown in FIG. 51A in an engaged position;

[0117]FIG. 52A is an exploded, perspective view of still anotherembodiment of an injector piston and syringe plunger interface system ofthe present invention;

[0118]FIG. 52B is an exploded perspective view of the piston/plungersystem shown in FIG. 52A;

[0119]FIG. 52C is a rear, perspective view of the piston/plunger systemshown in FIG. 52A in a disengaged position;

[0120]FIG. 53A is an exploded, perspective view of an alternateembodiment of the injector piston and syringe plunger interface systemsshown in FIGS. 51A-51C and 52A-52C;

[0121]FIG. 53B is an enlarged, perspective view of the piston/plungersystem shown in FIG. 53A in a disengaged position;

[0122]FIG. 53C is a cross-sectional view of the piston/plunger systemshown in FIG. 53A;

[0123]FIG. 53D is an exploded, perspective view of the piston/plungersystem shown in FIG. 53A;

[0124]FIG. 54A is a perspective view of a current syringe plunger;

[0125]FIG. 54B is an exploded, perspective of the plunger shown in FIG.54A;

[0126]FIG. 54C is a perspective view of an embodiment of a syringeplunger of the present invention;

[0127]FIG. 54D is an exploded, perspective of the plunger shown in FIG.54C;

[0128]FIG. 54E is a perspective view of another embodiment of a syringeplunger of the present invention;

[0129]FIG. 54F is an exploded, perspective view of the syringe plungershown in FIG. 54E;

[0130]FIG. 54G is a perspective view of yet another embodiment of thesyringe plunger of the present invention;

[0131]FIG. 54H is an exploded, perspective view of the syringe plungershown in FIG. 54G;

[0132]FIG. 55 is a side view schematic illustration of a secondpreferred embodiment of a front-loading syringe interface and syringesystem in accordance with the present invention, illustrating a releasemechanism for connecting a syringe to an injector housing;

[0133]FIG. 56 is an exploded, isometric, front view perspective of thesyringe interface and syringe system shown in FIG. 55;

[0134]FIG. 57 is an exploded, isometric, rear view perspective of thesyringe interface and syringe system shown in FIG. 56;

[0135]FIG. 58 is an exploded, isometric, rear view perspective of aportion of the syringe interface and syringe system shown in FIGS.55-57;

[0136]FIG. 59 is an exploded, isometric, rear view perspective ofanother portion of the syringe interface and syringe system shown inFIGS. 55-57, showing in detail the rear of a portion of a flex ring anda rotating ring of the interface/release mechanism;

[0137]FIG. 60 is an isometric, rear view of the syringe interface andsyringe system shown in FIGS. 55-59, detailing the connection of thesyringe to the release mechanism;

[0138]FIG. 61 is an exploded, isometric, front view perspectiveillustration of the portion of the present invention as shown in FIG.59, detailing the front of the rotating ring and a portion of the flexring thereof;

[0139]FIG. 62 is a partial, isometric, front view, perspectiveillustration of the rear portion of the syringe of the second preferredembodiment of the present invention, detailing the ridge and flangestructure thereof;

[0140]FIG. 63 is a partial, isometric, rear view, perspectiveillustration of the syringe shown in FIG. 62;

[0141]FIG. 64 is an isometric, rear view perspective illustration of thefront plate of the release mechanism of the second preferred embodimentof the present invention;

[0142]FIG. 65 is an isometric, front view perspective illustration ofthe front plate shown in FIG. 64;

[0143]FIG. 66 is an isometric, front view perspective illustration ofthe flex ring element of the release mechanism of the second preferredembodiment of the present invention, detailing several aspects thereof;

[0144]FIG. 67 is an isometric, rear view perspective illustration of theflex ring shown in FIG. 66;

[0145]FIG. 68 is an isometric, front view perspective illustration ofthe rotating ring element of the release mechanism of the secondpreferred embodiment of the present invention, detailing several aspectsthereof;

[0146]FIG. 69 is an isometric, rear view perspective illustration of therotating ring shown in FIG. 68;

[0147]FIG. 70 is an isometric, front view perspective illustration ofthe rear plate of the second preferred embodiment of the releasemechanism of the present invention, detailing several aspects thereof;

[0148]FIG. 71 is an isometric, rear view perspective illustration of therear plate shown in FIG. 70;

[0149]FIG. 72 is an isometric, front view perspective illustration ofthe syringe interface and syringe system of the second preferredembodiment of the present invention;

[0150]FIG. 73 is an isometric, rear view perspective illustration of thesyringe interface and syringe system shown in FIG. 72;

[0151]FIG. 74 is a cross-sectional schematic illustration of a portionof the syringe interface/release mechanism of the second preferredembodiment of the present invention before insertion of the syringe intothe interface/release mechanism;

[0152]FIG. 75 is a side view, cross-sectional schematic illustration ofthe same elements shown in FIG. 74, with the syringe partially insertedinto the interface/release mechanism;

[0153]FIG. 76 is a side view, cross-sectional schematic illustration ofthe same features of the second preferred embodiment of the presentinvention as shown in FIGS. 74 and 75, in this case illustrating thesyringe after it has been fully inserted into the interface/releasemechanism;

[0154]FIG. 77 is an end view, cross-sectional schematic illustration ofthe syringe and flex ring elements of the present invention as shown inFIG. 76, depicting the engagement of the syringe by the flex ring;

[0155]FIG. 78 is an end view, cross-sectional schematic illustration ofthe syringe and flex ring of the second preferred embodiment of thepresent invention, depicting the disengagement of the syringe from theflex ring after rotation of the syringe through a one quarter turn;

[0156]FIG. 79 is a perspective illustration of a related art syringe,showing the efficacy of the flange on the syringe for preventingcontrast media from entering the injector housing;

[0157]FIG. 80 is an isometric, front view, perspective illustration of afirst preferred embodiment of the injector piston and syringe plungerinterface system of the present invention;

[0158]FIG. 81 is an isometric, rear view perspective illustration of thepiston/plunger assembly depicted in FIG. 80;

[0159]FIG. 82 is an exploded, isometric view of the piston/plungerassembly depicted in FIGS. 80 and 81;

[0160]FIG. 83 is an exploded, isometric rear perspective illustration ofthe front end of the first preferred embodiment of the piston/plungerassembly of the present invention;

[0161]FIG. 84 is an exploded, isometric view of the same features of thepiston/plunger assembly illustrated in FIG. 83, taken from a slightlydifferent angle from the view shown in FIG. 83;

[0162]FIG. 85 is an isometric, front view illustration of the pistonfrom the piston/plunger assembly illustrated in FIGS. 80-82;

[0163]FIG. 86 is an isometric, side view illustration of the pistonillustrated in FIG. 85;

[0164]FIG. 87 is an isometric, front view illustration of the pistonsleeve of the piston/plunger assembly shown in FIGS. 80-82;

[0165]FIG. 88 is an isometric illustration of the collar element of thepiston/plunger assembly shown in FIGS. 80-82;

[0166]FIG. 89 is another isometric view of the collar depicted in FIG.88;

[0167]FIG. 90 is a third isometric view of the collar element depictedin FIG. 88;

[0168]FIG. 91 is an isometric end view illustration of the gripperexpander element of the first preferred embodiment of the piston/plungerassembly of the present invention;

[0169]FIG. 92 is a second isometric illustration of the gripper expanderdepicted in FIG. 91;

[0170]FIG. 93 is a third isometric illustration of the gripper expanderdepicted in FIGS. 91 and 92;

[0171]FIG. 94 is a first isometric illustration of one of the supportring grippers of the first preferred embodiment of the piston/plungerassembly of the present invention;

[0172]FIG. 95 is a second isometric illustration of the support ringgripper shown in FIG. 94;

[0173]FIG. 96 is another isometric illustration of the support ringgripper shown in FIGS. 94 and 95;

[0174]FIG. 97 is a first isometric illustration of the plunger capelement of the first preferred embodiment of the piston/plunger assemblyof the present invention;

[0175]FIG. 98 is a second isometric illustration of the plunger capshown in FIG. 97;

[0176]FIG. 99 is another isometric illustration of the plunger cap shownin FIGS. 97 and 98;

[0177]FIG. 100 is a fourth isometric illustration of the plunger capelement shown in FIGS. 97-99;

[0178]FIG. 101 is a first isometric illustration of the rubber coversupport ring element of the first preferred embodiment of thepiston/plunger assembly of the present invention;

[0179]FIG. 102 is a second isometric illustration of the rubber coversupport ring element shown in FIG. 101;

[0180]FIG. 103 is a third isometric illustration of the rubber coversupport ring element shown in FIGS. 101 and 102;

[0181]FIG. 104 is a fourth isometric illustration of the rubber coversupport ring element depicted in FIGS. 101-103;

[0182]FIG. 105 is an isometric, side view illustration of the rubbercover of the plunger of the first preferred embodiment of thepiston/plunger assembly of the present invention;

[0183]FIG. 106 is a second isometric illustration of the rubber covershown in FIG. 105;

[0184]FIG. 107 is a side view schematic illustration of a portion of thefirst preferred embodiment of the piston/plunger assembly of the presentinvention, showing the interrelation of the piston, collar, gripperexpander, support ring grippers and plunger cap thereof, theillustration showing the relationship of these elements when at rest orwhen the piston is moved toward the front end of the syringe;

[0185]FIG. 108 is a side view schematic illustration of the portion ofthe piston/pltnger assembly depicted in FIG. 107, in this case showingthe interrelation of the piston, collar, gripper expander, support ringgrippers and plunger cap thereof when the piston is moved/retractedtoward the rear end of the syringe;

[0186]FIG. 109 is a side view schematic illustration of a portion of thepiston/plunger assembly and the syringe, showing the interrelation ofthe syringe, rubber cover, support ring grippers, and rubber coversupport ring when the piston is moved/retracted toward the rear end ofthe syringe and the support ring grippers engage the rubber coversupport ring;

[0187]FIG. 110 is an isometric illustration of an alternate embodimentof a rubber cover for use with a plunger of the present invention;

[0188]FIG. 111 is a side view illustration of the rubber coverillustrated in FIG. 110;

[0189]FIG. 112 is a top view illustration of the rubber coverillustrated in FIG. 110;

[0190]FIG. 113 is a cross-sectional illustration of the rubber coverdepicted in FIG. 110;

[0191]FIG. 114 is an isometric, exploded illustration of an alternateembodiment of the syringe interface/release mechanism of the presentinvention;

[0192]FIG. 115 is an end-view, schematic illustration of anotherembodiment of the syringe interface/release mechanism of the presentinvention;

[0193]FIG. 116 is a cross-sectional illustration of an end portion ofthe second preferred embodiment of the syringe according to the presentinvention;

[0194]FIG. 117 is a cross-sectional illustration of an alternateembodiment of the syringe shown in FIG. 116;

[0195]FIG. 118 is a schematic representation of three embodiments ofgrooves that are provided in the rotating ring of the second preferredembodiment of the syringe interface/release mechanism of the presentinvention;

[0196]FIG. 119 is an isometric, exploded illustration of anotherembodiment of a syringe interface/release mechanism according to theteachings of the present invention;

[0197]FIG. 120 is an isometric, exploded illustration of still anotherembodiment of a syringe interface/release mechanism according to theteachings of the present invention;

[0198]FIG. 121 is a front view illustration of yet another embodiment ofa syringe interface/release mechanism according to the teachings of thepresent invention;

[0199]FIG. 122 is a side view illustration of the syringeinterface/release mechanism illustrated in FIG. 121;

[0200]FIG. 123 is an isometric, front view perspective of an alternateembodiment of the syringe shown in FIGS. 55-57;

[0201]FIG. 124 is an exploded, isometric, front view perspective of athird preferred embodiment of a front-loading syringe interface andsyringe system in accordance with the present invention;

[0202]FIG. 125 is an exploded, isometric, rear view perspective of thesyringe interface and syringe system shown in FIG. 124; and

[0203]FIG. 126 is an isometric, front view perspective of a syringeincorporating syringe encoding.

DETAILED DESCRIPTION OF THE INVENTION

[0204]FIG. 1 discloses an injector apparatus 10 of the general typedisclosed in U.S. Pat. No. 5,383,858 for injecting a liquid contrastmedia into a vascular system of an animal. Injector apparatus 10 has afront-loading construction. The apparatus of FIG. 1 utilizes a syringe12 capable of being front-loaded into a mounting assembly 14 associatedwith a front wall 16 of a housing 18 of an injector 20 by a firstreleasable mechanism 22. Syringe 12 is capable of functioning in aninjection operation without the use of a pressure jacket (although thesyringe may be used in an injector with a pressure jacket, as will bedescribed in greater detail in connection with FIGS. 4 and 5, below). Tothe extent not inconsistent with this disclosure, the disclosure of the'858 patent, which is assigned to Medrad, Inc., the Assignee of thesubject application, is incorporated herein by reference.

[0205] With reference to FIG. 1 and the first releasable mechanism 22,the mounting assembly 14 is provided with an essentially cylindricalinterface 26 for receiving a rearward end of syringe 12. Interface 26includes an annular surface 28, which may be cylindrical or conicallytapered. As best shown in FIGS. 6 and 7, annular surface 28 includes adistal ledge 29, which is engaged by tabs 30 on the rearward end ofsyringe 12. Syringe 12 is inserted into cylindrical interface 26 untiltabs 30 engage ledge 29 to secure syringe 12 to the injector 20.

[0206] Among other things, tabs 30 distribute the attachment force ofsyringe 12 to ledge 29 equally around the syringe. This helps tomaintain a connection between syringe 12 and ledge 29 even if syringe 12deforms or “ovals” under pressure during use. This overcomes a potentialshortfall with conventional front-loading injector systems, which maynot function as well if the syringe ovals under pressure during use.

[0207] Referring again to FIG. 1, syringe 12 comprises an elongated maintubular body or barrel 32 and a coaxial discharge injection section 34,interconnected by an intermediate conical portion 36. A plunger 38 isslidably positioned within the tubular body 32 and is connectable to asecond releasable mechanism 40 on a piston 42 in the injector housing18. Second releasable mechanism 40 is formed in part by plunger 38 andin part by piston 42, as set forth in greater detail below.

[0208] Piston 42 and plunger 38 cooperate to eject fluid containedwithin syringe 12 in a desired quantity and at a desired rate. Secondreleasable mechanism 40 is designed to facilitate axial movement ofplunger 38 in either direction when actuated. Second releasablemechanism 40 is also designed to engage or disengage plunger 38 frompiston 42 no matter where plunger 38 sits in tubular body 32. Further inthis connection, the actuating mechanism, which reciprocates the plunger38 in the syringe tubular body 32, comprises piston 42 or a reciprocabledrive member. The drive member or piston 42, while reciprocable, doesnot need to be rotatable.

[0209] With reference to FIG. 1, to be mounted, syringe 32 is insertedinto interface 26 in mounting assembly 14. As best shown in FIGS. 6 and7, tabs 30 initially move past annular surface 28 where they engageledge 29 to securely hold syringe 12 to mounting assembly 14. As bestshown in FIGS. 2 and 7, mounting assembly 14 further includes aforwardly projecting annular ring or collar 44, which functions toassure perpendicular engagement between plunger 38 and piston 42. Asexplained above, forwardly projecting annular ring or collar 44 alsofunctions as a seal between a flange 46 on syringe 32 and mountingassembly 14.

[0210] Resilient annular sealing flange 46 surrounds tubular body 32 ofsyringe 12 and is disposed forward of tabs 30 a preselected distanceessentially equal to a width of annular surface 28. Thus, when syringe12 is inserted into interface 26 in mounting assembly 14 until sealingflange 46 engages annular ring 44, annular ring 44 and flange 46 createa seal between syringe 12 and mounting assembly 14.

[0211] The foregoing mounting arrangement possesses a number ofadvantages. The attachment of tabs 30 to the periphery of the rearwardportion of syringe 12 minimizes wobble of syringe 12 during an injectionoperation. While minimizing wobble, tabs 30 also permit syringe 12 torotate freely within interface 26. Tabs 30 also prevent syringe 12 fromdisengaging from injector 20. The seal between annular ring 44 andflange 46 also prevents contrast media spilled from discharge end 34 ofsyringe 12 from flowing into injector housing 18 (as illustrated in FIG.2) and eliminates the need for constructing the respective parts toexcessively tight tolerances. To enhance the sealing capability betweenflange 46 and annular ring 44, a suitable O-ring (not shown) may beprovided optionally therebetween.

[0212] With further reference to FIG. 1, the apparatus also includes asystem for transmitting syringe information from syringe 12 to aninjector controller 51. Syringe 12 is provided with an encoding device48 forward of tabs 30 but rearward of flange 46. Encoding device 48 maybe a bar code or any other suitable encoding device known to thoseskilled in the art. When attaching syringe 12 to the mounting assembly14, if syringe 12 is rotated after tabs 30 engage ledge 29, a sensor 50is provided in annular surface 28 to read the encoding device 48. Sensor50 then forwards the associated signals to injector controller 51, whichinterprets the signals and modifies the function of the injector 20accordingly. Examples of the information which could be encoded onencoding device 48 include dimensions of syringe 12, volume of syringe12, content of syringe 12 (in the case of a pre-filled syringe),manufacturing information such as lot numbers, dates and tool cavitynumber, recommended contrast media flow rates and pressures, andloading/injection sequences.

[0213] As an alternative to encoding device 48 being a bar code,encoding device 48 also could include machine-readable raised orrecessed surfaces. The raised or recessed surfaces could then be read byinjector sensor 50, mounted in annular surface 28, in a manner similarto that for reading a bar code. In addition to encoding device 48, onemight also use a mechanically readable device (e.g. a slot, hole, orprojection on the syringe 12 or plunger 38) to register against a switchon the mounting assembly 14. Alternatively, an optically readable device(e.g. characters, dots and other geometric shapes) could be employed tosend information concerning the type of syringe used to the intelligentcircuits of injector 20.

[0214] In FIG. 1, since syringe 12 is being used in this embodimentwithout a pressure jacket, for strength and visibility of the contentsof syringe 12, the syringe 12 may be formed of a clear PET polyestermaterial. In the alternative, the wall of syringe 12 may be formed ofpolypropylene reinforced by providing a series of annular ribs ontubular body 32 of syringe 12 in longitudinally spaced relationship.(This arrangement is illustrated in FIG. 5 of the '858 patent.) Asdiscussed in the '858 patent, by suitably spacing the ribs along thelength of tubular body 32, such as in equal increments, the ribs alsocan perform the dual function of serving as volumetric gradations forthe purpose of indicating the amount of contrast media in syringe 12.

[0215] With reference to FIGS. 1 and 2, tubular body 32 of syringe 12also may be provided with an indicating mechanism 52 for readilydetecting the presence or absence of a liquid contrast media in syringe12. In this instance, detecting mechanism 52 includes a plurality ofintegrally molded, textured dots on syringe 12, which provide a visualindication of whether the syringe contains liquid or air. Morespecifically, when viewed against an air background, dots 52 appearoval-shaped, but when viewed against a liquid contrast media background,which has a different index of refraction than air, dots 52 appearcircular. The details of indicating mechanism 52 are described in detailin U.S. Pat. No. 4,452,251, assigned to Medrad, Inc., the Assignee ofthe subject application. To the extent not inconsistent with the presentdisclosure, the contents of U.S. Pat. No. 4,452,251 are incorporatedherein by reference.

[0216]FIG. 3 illustrates the internal construction of the syringedischarge end 34. Specifically, while a rearward portion 54 of dischargeend 34 is of tapered conical construction, a forward connector portion56 is of generally cylindrical construction and formed with internalscrew threads 58 for attaching a connecting tube to discharge end 34.Further, an injection nozzle 60 of reduced diameter is disposed withinthe screw-threaded cylindrical connector portion 56 and is integrallymolded with tapered rearward portion 54 of discharge end 34 adjacent thepoint at which the tapered and cylindrical portions merge together.

[0217]FIGS. 4 and 5 illustrate an alternate embodiment of the presentinvention in which a front-loading syringe 112 is mounted on the frontof a pressure jacket 170, preferably formed of a strong clear plastic,such as polycarbonate. Pressure jacket 170 is in the form of anelongated tubular member that is suitably mounted at its rearward end ina mounting assembly 124 on housing front wall 116, by fitting the flangeof pressure jacket 170 into the collar on the mounting assembly 124.Pressure jacket 170 also has a forward open end 172 for receiving thesyringe 112.

[0218] In this embodiment, an annular surface 174 with a distal ledge175 is provided adjacent to the forward open end 172 of the pressurejacket 170. Annular surface 174 is similar in construction to annularsurface 28 in the embodiment illustrated in FIGS. 1 and 7. Similarly, atubular body 132 of syringe 112 includes tabs 180 at a position adjacentits forward end for engagement with ledge 175 when tubular body 132 hasbeen inserted into pressure jacket 170.

[0219] In addition, at the forward end of syringe 112, on opposite sidesof a discharge end 134, a pair of reinforcing, loop-shaped handles 162,for facilitating handling of the syringe 112, is integrally molded withdischarge end 134 and a tapered conical intermediate portion 136. Inother respects, while not specifically disclosed and described, it is tobe understood that various other features of the embodiment of theinvention disclosed in FIGS. 1-3, 6 and 7 may be incorporated into theembodiment of FIGS. 4 and 5, as desired.

[0220] In use, the syringe 112 of FIGS. 4 and 5 may be mounted inpressure jacket 170 with piston 142 of injector 120 either in aretracted position, as shown in FIG. 4, or in an advanced position, asshown in FIG. 5. For example, with piston 142 in the retracted position,as shown in FIG. 4, plunger 138 is disposed at the rearward end ofsyringe 112. Syringe 112 then is inserted into the open end 172 of theforward end of pressure jacket 170 until second releasable mechanism 140engages with plunger 138.

[0221] In FIG. 5, in which piston 142 is in a forward position, themounting of syringe 112 into pressure jacket 170 is the same as shown inFIG. 4, except that plunger 138 also is in its forward position insyringe 112. In other respects, the mounting of syringe 112 on pressurejacket 170 is essentially the same as previously described with respectto FIG. 4. However, having syringe plunger 138 and piston 142 in theirforward positions, as shown in FIG. 5, has several advantages over therearward position arrangement of FIG. 4. For example, because syringeplunger 138 and piston 142 are already in their forward positions, it isnot necessary to move them forward to expel air from the syringe 112 inpreparation for a syringe-filling operation. Rather, plunger 138 andpiston 142 can immediately be retracted to aspirate fluid into thesyringe 112. Similarly, after an injection operation has been completed,additional time is saved by not having to retract plunger 138 and piston142 in preparation for a next injection operation.

[0222] In summary, a new and improved system by which an injectionsyringe, such as syringe 12 in the embodiment of FIGS. 1-3, can bereadily mounted upon and/or removed from injector housing 18, has beendisclosed. For this purpose, the first releasable mechanism 22, by whichsyringe 12 is attached to or removed from injector housing 18, andsecond releasable mechanism 40, by which plunger 38 of syringe 12 isdrivingly connected to or released from piston 42 of injector 20cooperate to produce their respective connections and disconnectionssimultaneously and/or independently. Another advantage is that plunger38 is capable of being placed in a driven or undriven state at any pointalong its path, whereby syringe 12 may be disengaged from injector 20without having to retract piston 42, or having to first disconnectsyringe 12 from a patient being injected before retracting piston 42.

[0223] Other desirable features of the invention include theconstruction of first releasable mechanism 22, in which syringe 12 ismounted upon injector housing 18 with a secure fit, which isadvantageous from the standpoint of minimizing syringe wobble anddisengagement during an injection operation, and eliminating the needfor excessively tight manufacturing tolerances. Encoding device 48 onsyringe 12, in cooperation with sensor 50 on injector 20, also isadvantageous from the standpoint of providing “custom programming” ofinjector 20. Elimination of a pressure jacket also is desirable from thestandpoint of better visibility of the contents of syringe 12, betterheat transfer to the syringe contents and decreased cleaning andmaintenance otherwise needed due to, e.g., scratching or contaminationwith contrast media of the pressure jacket.

[0224] In order to eliminate the need for a pressure jacket, syringe 12also may be made of a relatively strong clear plastic, or may beprovided with annular reinforcing ribs (not shown), which may be spacedto function as volumetric gradations. Further, detection of the presenceof air in syringe 12 is facilitated by the indicating mechanism 52 inFIGS. 1 and 2, in the form of dots 52 molded into syringe tubular body32. Dots 52 appear visually as either oval-shaped or circular, dependingupon whether the tubular body contains air or liquid, respectively. Inaddition to functioning as a part of first releasable mechanism 22 forsyringe 12, syringe resilient annular flange 46 also cooperates withannular ring 44 to create a seal to prevent contrast media spilled fromthe injection end of syringe 12, from flowing into injector 20, as shownin FIG. 2. The embodiment of the invention shown in FIGS. 4 and 5provides a system by which various other advantages, including timesavings in syringe-filling and syringe-changing operations, can beachieved utilizing a pressure jacket, such as pressure jacket 170mounted on injector housing front wall 116.

[0225]FIG. 6 illustrates a cross-section of syringe 12 after it has beeninserted into injector 20 so that tabs 30 engage ledge 29. Tabs 30 arepreferably substantially V-shaped members that preferably form a ringencircling the rearward end of tubular body 32. Alternately, one or moretabs may be separately disposed around the rearward end of the body 32.Each of tabs 30 on the ring has a first end 62 and a second end 64. (Anenlarged, perspective illustration of the ring of tabs 30 is shown inFIG. 8.) As shown in FIG. 8, first ends 62 of tabs 30 engage ledge 29when syringe 12 is inserted into interface 26 of injector 20. First ends62 of tabs 30 are separated from one another by gaps 66 around theperiphery of tubular body 32 so that they are flexible and can easilycompress. Second ends 64 of tabs 30, on the other hand, form a ring thatattaches to tubular body 32.

[0226] Syringe 12, therefore, is easily connected to the injector 20simply by inserting the rearward end of tubular body 32 into cylindricalinterface 26. During insertion of tubular body 32 into cylindricalinterface 26, annular surface 28 compress first ends 62 of tabs 30 untilfirst tabs 62 clear ledge 29. Once first ends 62 clear ledge 29, theyspring open and engage ledge 29 to prevent the removal of tubular body32 from interface 26.

[0227] Removal of syringe 12 from housing 20 is enabled by areciprocating collar 68 that is disposed within injector 20 at alocation behind syringe 12 (once inserted into cylindrical interface26). Reciprocating collar 68 is preferably a cylindrical member that canmove in both forward and rearward directions, as illustrated by thearrow in FIG. 7. During an injection operation, reciprocating collar 68is in its rest position behind tabs 30 so that first ends 62 remainengaged with ledge 29. Upon completion of the injection operation, inorder to remove syringe 12 from interface 26, reciprocating collar 68 ispushed forward toward ledge 29 by an actuating mechanism (not shown) ormanually so that it compresses first ends 62 so that they can easilyslide out from behind ledge 29. Syringe 12 then can be easily removedfrom injector 20.

[0228] Alternatively, tabs 30 may be caused to disengage from ledge 29by retracting annular surface 28 in the direction of arrow 1100 in FIG.33. To do this, annular surface 28 is made of a number of segments 1102,all of which can retract to release syringe 32. In still anotheralternative embodiment as illustrated in FIG. 34, a portion of the innersurface 1104 may be moved inwardly in the direction indicated by arrow1106 to collapse tabs 30 so that syringe 32 may be disengaged from ledge29. Other embodiments of these two arrangements will be readilyunderstood by those skilled in the art.

[0229] In the case where syringe 112 is to be inserted into a pressurejacket 170 (as illustrated in FIGS. 4 and 5), tabs 180 serve the samefunction as tabs 30, except of course that they are located toward theforward end of syringe 112. In fact, but for the location of tabs 180 ontubular body 132, it is contemplated for the present invention that tabs180 have the same construction as tabs 30. When tabs 180 are insertedthrough open end 172 of pressure jacket 170, annular surface 174compresses first ends 62 of tabs 180 until they clear ledge 175. Syringe112 is then securely held in place. When it becomes necessary to removesyringe 112 from pressure jacket 170, a reciprocating collar 68 extendsforward within the pressure jacket 170 (as described in more detailbelow) to compress first ends 62 so that they no longer engage ledge174. Syringe 112 can then be removed from pressure jacket 170.

[0230] It is not necessary for tabs 30, 180 to have a V-shapedappearance as illustrated in FIGS. 1 and 4-8, however. It iscontemplated for the second embodiment of tabs 30 that they have ab-shaped appearance, as illustrated in FIG. 9. When tabs 30 have ab-shaped appearance, they may be formed integrally with the end ofsyringe 412. Tabs 30, when they have a b-shaped appearance, have bulbousfirst ends 70 that extend outwardly from second ends 72, which areseparated from adjacent tabs 30 by gaps 71 (as best shown in FIGS. 14and 15). As with first ends 62, first ends 70 engage ledge 29 whensyringe has been inserted into injector housing 18. As with first ends62, reciprocating collar 68 acts upon first ends 70 to disengage themfrom ledge 29 when syringe 412 is to be removed from injector 20.

[0231] For each of the embodiments of tabs 30 contemplated by thepresent invention, it is also contemplated that the number of tabs usedmay be varied while remaining within the scope of the present invention.For example, for syringe 212, illustrated in FIGS. 10 and 11, it iscontemplated that only one tab is provided at the end of the syringe. InFIGS. 10 and 11, only one tab 30 with first end 70 and second end 72 isillustrated. It should be understood, however, that tab 30 with firstend 62 and second end 64 could be easily substituted therefor.

[0232] While a single tab 30 may be used, preferably the syringe has atleast two tabs, because the tabs should flex in order to functionoptimally. Such a syringe 312, with at least two tabs, is illustrated inFIGS. 12 and 13. When two tabs are included on syringe 312, it iscontemplated that they be disposed on opposite sides of tubular body 32to add stability to the secure engagement of syringe 312 to injector 20.The tabs may be appropriately sized and optionally may be of differentcircumferential dimension.

[0233] In an alternate embodiment of the pressure jacketed injectorsystem shown in FIG. 32, it is contemplated that a syringe cap 1000could be provided at the end of the pressure jacket 1002 to hold asyringe 1032 therein. Alternately, cap 1000 could be attached to ormolded as a part of syringe 1032 and need not be a separate element. Asshown in FIG. 32, pressure jacket 1002 is a modified version of pressurejacket 170 illustrated in FIGS. 4 and 5. According to the teachings ofthe present invention, cap 1000 includes tabs 1004 about its periphery.Tabs 1004 engage a ridge 1006 that encircles the end of pressure jacket1002. To disengage tabs 1004 from ridge 1006, a reciprocating ring 1008slides along the exterior of pressure jacket 1002. Ring 1008 includes atapered surface 1010 to facilitate removal of tabs 1004 from ridge 1006.The actuator of ring 1008 is not shown. However, those skilled in theart will readily recognize that ring 1008 may be operated eithermanually, mechanically, or electrically (or in any other fashionsuitable to disengage tabs 1004 from ridge 1006).

[0234] In another alternate embodiment of the apparatus described inrelation to FIG. 32, the tabs could extend from the cap (which could beseparate from, attached to, or molded with the syringe) to engageannular member 174 at the end of pressure jacket 170 in the same waythat tabs 180 engage annular member 174 in the embodiment illustrated inFIGS. 4 and 5. As with the embodiment illustrated and described inrelation to FIGS. 4 and 5, a reciprocating collar should then bepositioned within pressure jacket 170 to disengage the tabs from theannular member.

[0235] The elements for the releasing mechanism are illustrated in FIGS.38 and 39. There, reciprocating collar 1402 is shown internal topressure jacket 170. As illustrated, reciprocating collar 1402 isdisposed at the end of at least two supports 1404 that are also withinthe interior of pressure jacket 170. To accommodate supports 1404,interior wall 1406 of pressure jacket 170 includes at least two tracks1408 in which supports 1404 slide. When syringe 1032 is to be removedfrom pressure jacket 170, reciprocating collar 1402 is moved forwardwithin pressure jacket 170 to disengage the tabs on syringe 1032 fromengagement with annular member 174.

[0236] This arrangement also may be used in connection with the pressurejacket system illustrated and described in connection with FIGS. 4 and5. When syringe 132 is to be removed from pressure jacket 170,reciprocating collar 1402 is moved forward within pressure jacket 170 tocompress tabs 180 so that they no longer engage annular member 174. Oncetabs 180 are clear of annular member 174, syringe 132 maybe removed frompressure jacket 170.

[0237] In the case where syringe 112 is to be inserted into pressurejacket 170 as shown in FIGS. 4 and 5, b-shaped tabs 190 may be added tothe forward end of syringe 112 in the same manner that tabs 180 wereapplied. As shown in FIG. 16, tabs 190 essentially comprise a ring 74from which second ends 72 of tabs 190 extend in a rearward direction.Ring 74 with tabs 190 form a V-shaped structure in cross-section, asillustrated in FIG. 17. As with tabs 180, when tabs 190 are insertedinto pressure jacket 170 (as illustrated in FIGS. 4 and 5), they arecompressed until they clear annular surface 174, whereupon they expandto engage ledge 175. Tabs 190 hold syringe 112 securely in pressurejacket 170 until disengaged by reciprocating collar 68.

[0238] The installation and removal of syringe 412 is illustrated inFIGS. 18-20. In FIG. 18, syringe 412 is shown prior to insertion intoinjector front wall 16. Reciprocating collar 68 is shown in a rest statebehind where first ends 70 of tabs 30 will rest after they clear annularsurface 128 and rest against distal ledge 129. In this embodiment,annular surface 128 is illustrated with a tapered cross-section ratherthan the cylindrical cross-section shown in FIGS. 7 and 9. A taperedcross-section may facilitate insertion of syringe 412 into interface 26because the taper may help to squeeze first ends 70 of tabs 30 duringinsertion of syringe 412 into injector 20. In addition, annular surface128, when tapered, acts as a guiding surface for syringe 412 (or anyother embodiment disclosed) so that syringe 412 may be inserted intofront wall 16 at even greater angular approaches. In other words,syringe 412 may be inserted easily into front wall 16 even when syringe412 is not oriented exactly with the central axis of interface 26.

[0239] Once syringe 412 has been fully inserted into front wall 16, tabs30 expand to engage ledge 129, as illustrated in FIG. 19. Syringe 412 isthen securely held in place. As shown in FIG. 19, reciprocating collar68 remains in its rest position until after the injection operation iscompleted.

[0240] After the injection operation is completed, reciprocating collar68 is moved forward to compress first ends 70 of tabs 30 to disengagetabs 30 from ledge 129. FIG. 20 shows reciprocating collar 68 in thisforward position. The compression of tabs 30 is also illustrated. Thesyringe 412 may then be removed from injector 20.

[0241] The present invention also contemplates that it may be desirableto connect a syringe to an adapter 500 before connecting the syringe toinjector 20. The adapters could be disposable or re-useable, as would beunderstood by those skilled in the art. The syringe may be of differentconstruction from that disclosed herein, as would be understood by thoseskilled in the art. An adapter for a syringe is described in U.S. Pat.No. 5,535,746, issued to Hoover et al. on Jul. 16, 1996, the disclosureof which is incorporated herein by reference. Other patents that areexemplary of adapters include U.S. Pat. No. 5,520,653 and WO 97/36635,both of which are assigned to the Assignee of the present applicationand are incorporated herein by reference.

[0242] In the embodiment illustrated in FIG. 21, a syringe 412 with tabs30 having a b-shaped appearance snap-fits into a forward end 502 ofadapter 500. Of course, tabs with the V-shaped cross-section may besubstituted therefor. Adapter 500 includes a annular surface 528 with adistal ledge 529 within its forward end 502 to which first ends 70 oftabs 30 engage to hold syringe 412 securely in place. Flange 46 ofsyringe 412 may or may not be included to engage with forward end 502 ofadapter 500 to prevent contrast medium, should it leak, from enteringinjector housing 18 through adapter 500. The rearward end 504 of adapter500 also preferably includes a flange 546 that mates with annular ring44 on mounting assembly 14 of injector 20. Flange 546 serves the samefunction as flange 46 on syringe 12, namely to prevent contrast medium(or whatever fluid is included in syringe) from entering the injector20.

[0243] If adapter 500 is attached to syringe 32, piston 42 may need tobe adapted to accommodate the increased length of the overallconstruction. If so, a piston extender or adapter (not shown) may beattached to the end of piston 42, as would be understood by thoseskilled in the art. Alternatively, piston 42 could be constructed sothat it is long enough to accommodate syringes 32 of varying lengths.

[0244] In this particular embodiment, adapter 500 includes conventionalconnector elements 506, such as those described in U.S. Pat. No.5,535,746 or U.S. Pat. No. 5,383,858. So designed, adapter 500 permitssyringe 412 to be connected to an injector that is designed to acceptonly syringes with conventional connector elements 506.

[0245] As shown in FIG. 22, in an alternate embodiment of the adapter,it may be necessary to adapt a conventional syringe for use in aninjector designed to accept the syringes of the present invention. Here,adapter 600 includes tabs 630 at its rearward end 604. Tabs 630 act andfunction like tabs 30 to secure adapter to housing 18 by engaging ledge29 on mounting assembly 14. Tabs 630 are disengaged from ledge 29 byreciprocating collar 68. Adapter 600 may also include a flange 646 as inthe other embodiments that have been described above. While adapter 600is shown with a syringe having a ridged end inserted therein, it shouldbe understood that adapter 600 could be easily designed so that itsforward end 602 can accept conventional connector elements, such asthose described in U.S. Pat. No. 5,535,746 or U.S. Pat. No. 5,383,858.

[0246]FIGS. 23 and 24 illustrate two perspective views of thecombination of the syringe 412 and adapter 600. In this embodiment,flange 46 has been omitted. However, as illustrated in FIG. 22, flange46 may be included. Naturally, as with syringe 212 (shown in FIGS. 10and 11) and with syringe 312 (shown in FIGS. 12 and 13), the adapter mayinclude only one tab, two tabs, or more than two tabs 630. FIGS. 23 and24 illustrate adapter 600 with a plurality of tabs.

[0247] Two embodiments of second releasable mechanism 40 for engagingand releasing the syringe plunger and the injector piston will now bedescribed with respect to FIGS. 25-29. FIG. 25 illustrates anelectromagnetic release mechanism. FIGS. 26-29 illustrate anelectromechanical release mechanism.

[0248] As shown in FIG. 25, plunger 738 may be releasably connected topiston 742 through an electromagnetic device. A forward end 702 ofpiston 742 is provided with an electromagnetic coil 704 that can beactivated by applying a current through leads 706 that extend throughpiston 742. At its rearward end 707, plunger 738 includes a magneticallyattractive ring 708, made of iron, for example, which is attracted toelectromagnetic coil 704 when electromagnetic coil 704 is activated. Thecross-sections of forward end 702 of piston 742 and of recess 710 inrearward end 707 of plunger 738 are cylindrical. This permits theengagement of piston 742 with plunger 738 regardless of the orientationof plunger 738 in the syringe.

[0249] Second releasable mechanism 40, as illustrated in FIG. 25,operates as follows. When a syringe has been inserted into the interfaceon the injector housing 18, piston 742 is extended into the syringeuntil its forward end 702 mates with recess 710 of plunger 738.Electromagnetic coil 704 may then be activated to retract plunger 738.The attraction between magnetically attractive ring 708 andelectromagnetic coil 704 holds plunger 738 to the end of piston 742during rearward movement of piston 742. Alternatively, electromagneticcoil 704 may be activated before piston 742 is extended into the syringeto mate with plunger 738. Once plunger 738 and piston 742 areelectro-magnetically attracted to one another, piston 742 may be movedas required within the syringe. To disengage piston 742 from plunger738, or to retract piston 742 without retracting plunger 738, one needonly disengage the power supplied to electromagnetic coil 704. Ofcourse, the piston 742 may advance the plunger 738, for example, duringan injection, without activating electromagnetic coil 704.

[0250] The second embodiment contemplated for second releasablemechanism 40 involves an electromechanical connection between the pistonand the plunger. This embodiment is illustrated in FIGS. 26-29.

[0251] In FIGS. 26-29, piston 842 has a forward end 802 that engageswith a recessed area 804 formed in a rearward end 806 of plunger 838.Forward end 802 of piston 842 includes protrusions 808 that retractablyextend therefrom. Protrusions 808 engage an indentation or channel 810formed in the plunger 838, as illustrated in FIG. 27. A member 812 isenclosed by piston 842 and forward end 802. Member 812 is actuated bymechanism 814, also contained within piston 842. Mechanism 814 receivespower through leads 816.

[0252] As shown in FIGS. 28 and 29, protrusions 808 are essentiallyrectangular. They are connected to one another through resilient members818. Resilient members 818 bias protrusions 808 so that they do notprotrude from forward end 802 of piston 842, as shown in FIG. 29.

[0253] The operation of second releasable mechanism 40 will now bedescribed in connection with FIGS. 26-29. When a syringe has beeninserted into front wall 16 of injector 20, piston 842 is extendedforward to meet with plunger 838. When piston 842 extends forward,mechanism 814 is deactivated so that member 812 is in a retractedcondition, as shown in FIG. 29. In other words, member 812 is retractedso that it does not sit between protrusions 808. As a result, resilientmembers 818 bias protrusions 808 so that they do not extend outside offorward end 802 of piston 842, as shown in FIG. 29.

[0254] Once forward end 802 of piston 842 mates with recessed area 804in plunger 838, mechanism 814 is activated so that member 812 extendsforward to sit between protrusions 808, thereby forcing protrusions 808to extend outside of forward end 802 of piston 842. Protrusions 808,once extended, extend into channel 810 within plunger 838. Once soarranged, piston 842 is connected to plunger 838 so that rearwardmovement of piston 842 translates directly into a corresponding rearwardmovement of plunger 838.

[0255] When it becomes necessary to disengage the syringe from theinjector, or to retract piston 842 without retracting plunger 838,mechanism 814 is activated to withdraw member 812 from betweenprotrusions 808. Once withdrawn, resilient members 818 bias protrusions808 so that they no longer engage channel 810. Piston 842 may then bewithdrawn from plunger 838.

[0256] Two additional second releasable mechanisms 40 will now bedescribed with reference to FIGS. 35-37.

[0257] In the embodiment illustrated in FIG. 35, plunger 1238 may bereleasably connected to piston 1242 through expansion of an elastomericmember 1202 disposed at a forward end thereof. Elastomeric member 1202is a cylindrical element with external walls 1204 and internal walls1206. A rod 1208 extends through piston 1242 and connects to an actuator1210 at a forward end of rod 1208 closest to plunger 1238. Actuator 1210has a frustoconical shape on a side facing elastomeric member 1202. Thefrustoconical shape defines an inclined surface 1212 on actuator 1210.The diameter of elastomeric member 1202 is slightly smaller than thediameter of the hole 1214 in plunger 1238. Also, the diameter ofactuator 1210 is smaller than the diameter of hole 1214.

[0258] The operation of the second releasable mechanism 40 illustratedin FIG. 35 will now be described. Because the diameter of hole 1214 inplunger 1238 is larger than the diameter of elastomeric member 1202 andof actuator 1210, when piston 1242 is pushed forward, elastomeric member1202 and actuator 1210 easily fit into hole 1214. Plunger 1238 can thenbe advanced by piston 1242 without a connective engagement existingtherebetween. However, once positioned in this manner, to connectivelyengage the plunger 1238 (e.g., to retract plunger) actuator 1210 ispulled toward elastomeric member 1202 by rod 1208, as shown by arrow1216 in FIG. 35. The pressure from actuator 1210 compresses elastomericmember 1202 so that external sides 1204 swell or expand from theirunstressed condition. The approximate shape of the swelled walls 1218 ofelastomeric member 1202 is shown in dotted line format in FIG. 35.Swelled walls 1218 engage walls 1220 of hole 1214 so that piston 1242releasably engages plunger 1238. Plunger 1238 can now be retracted to,for example, aspirate fluid into the syringe.

[0259] The embodiment of second releasable mechanism 40 shown in FIGS.36-37 will now be described. As shown in FIGS. 36-37, plunger 1338engages piston 1342 through segmented member 1302. Segmented member 1302is made of a number of separate elements 1304 as shown in the end viewillustration of FIG. 37. Separate elements 1304 may be made from anysuitable material, such as an elastomeric material, so long as thematerial preferably (1) can substantially withstand repeated deformationand (2) returns substantially to its original condition when no longersubject to a deforming stress. Segmented member 1302 is disposed at aforward end of piston 1342. A rod 1306 extends through the middle ofpiston 1342 and extends at least partially into a central bore 1308 ofsegmented member 1302.

[0260] To releasably connect plunger 1338 with piston 1342, piston 1342is moved forward until segmented member 1302 is disposed within a hole1310 formed in plunger 1338. Rod 1306 is then moved forward, in thedirection shown by arrow 1312, until rod 1306 is at least partiallydisposed within segmented member 1302. Since the diameter of rod 1306 isgreater than the diameter of bore 1308, the insertion of rod 1306 intobore 1308 pushes segmented members 1304 outwardly until they reach adeformed position 1314 shown in dotted lines in both FIG. 36 and FIG.37. When deformed, segmented members 1304 engage walls 1316 of hole 1310in plunger 1338 to create a releasable engagement between plunger 1338and piston 1342.

[0261] For each of the second releasable mechanisms described in FIGS.25-29 and 35-37, the advantage that the mechanisms provide is that thepiston need not be oriented in any specific manner with the plunger inorder to facilitate a connection between the piston and plunger.Regardless of the orientation of the piston and the plunger, the two caneasily mate with one another and can be easily disengaged from oneanother.

[0262] In addition, if for example a prefilled syringe is mounted on theinjector, it may not be necessary to retract the plunger within thesyringe to draw fluid within the syringe for subsequent injection. Insuch a case, the piston may be operated in a “push-only” mode that doesnot require engagement between the piston and the plunger. If operatedin this manner, the engagement mechanism need not be activated at all.Alternatively, if the injector is designed to handle only prefilledsyringes, no readily releasable mechanism need be provided.

[0263] The plunger of the present invention may also include a pressuresensor like the sensors described in U.S. Pat. No. 5,808,203, issued toNolan, Jr. et al. on Sep. 15, 1998, and assigned to the Assignee of thepresent application. The disclosure of U.S. Pat. No. 5,808,203 isincorporated herein by reference, to the extent that it is notinconsistent with the instant disclosure.

[0264]FIGS. 30 and 31 illustrate the sensor that can be included in theplunger of the present invention. Plunger 938 preferably comprises abase 902 with a passage 904 therethrough. A sensing member 906 isdisposed within passage 904 to be in operative contact with a portion Pof contact surface 908. Sensing member 906 is preferably biased forward,for example, via a spring 910. As fluid pressure within the syringe (notshown) increases, portion P of contact surface 908 is deformed as shownin FIG. 31. This deformation of portion P causes sensing member 906 tomove rearward through passages 904 and 912 and 914 in piston 942. Themovement of sensing member 906 is monitored with a sensor 916 preferablydisposed within piston 942. Because the degree of movement of sensingmember 906 is a function of the pressure of the fluid medium within thesyringe, the pressure of the fluid medium can be determined therefrom.Sensor 916 is preferably connected to a data collection and/or controldevice via leads 918.

[0265] While FIGS. 30 and 31 describe one possible embodiment of asensor that can be incorporated into the plunger of the presentinvention, it should be noted that any other suitable sensor may beincluded. In addition, the sensor need not detect only the pressure ofthe fluid. As would be understood by those skilled in the art, thesensor may measure a number of different parameters including amount,pressure and density of the fluid in the syringe.

[0266] Also, the plunger may contain encoding elements that are read orsensed by the injector or injector piston to identify the syringe and/orits contents. In this embodiment, the encoding elements, such as anintegrated circuit, are included on the plunger rather than the syringe.The encoded elements then may be read electronically when the plungercontacts the piston. The plunger may contain information such as thecontents and volume of the syringe as well as other information neededfor the procedure or for billing purposes. One example of such a systemis described in PCT Publication No. WO 99/65548, which is incorporatedherein by reference.

[0267] The present invention is often shown and described herein interms of cooperating syringe interfaces and syringes. The terms “syringeinterface” and “syringe interfaces” as used herein can be incorporatedin or integrated with new medical injectors or configured as syringeadapters mountable on or associated with existing or conventionalmedical injectors, such as the injector shown and described in U.S. Pat.No. 5,383,858, the contents of which are hereby incorporated byreference, to allow the installation of the syringes of the presentinvention thereon.

[0268] FIGS. 40A-40C illustrate another embodiment of a front-loadingsyringe interface and syringe system 1500 in accordance with the presentinvention. The system 1500 includes a syringe 1512 and a syringeinterface 1514. The syringe 1512 includes a body or barrel portion 1516having a rear end 1520 and a front end 1517 defining a fluid dischargeend 1518. Preferably, at least one tab or mounting member 1522 isassociated with the barrel portion 1516 adjacent to or at the rear end1520 of the syringe 1512. In addition, a flange 1524 is preferablypositioned forward of the mounting member 1522 to facilitate theengagement of the syringe 1512 to the syringe interface 1514 and/or toprevent fluid expelled from the discharge end 1518 of the syringe fromentering into the syringe interface 1514 and the injector (not shown),as described in more detail in U.S. Pat. No. 5,383,858.

[0269] Preferably, the mounting member 1522 is disposed around thecircumference of the barrel portion 1516 and includes an inclinedsurface 1526 that defines a shoulder 1528. The function of the mountingmember 1522 will be described in more detail below. Alternately, themounting member 1522 may extend around only a portion of thecircumference of the barrel portion 1516 or may be formed in discretesegments.

[0270] (Unless otherwise noted, the syringe 1512 (and its componentsparts) described above applies to the remaining embodiments of thepresent invention discussed and described below with respect to FIGS.40A-47F.)

[0271] As best shown in FIGS. 40A and 40C, the syringe interface 1514 isin an “open” position ready to accept the syringe 1512. The syringeinterface 1514 includes a base member 1530 and two cooperatingsyringe-retaining members 1532. However, in alternate embodiments, threeor more retaining members 1532 could be provided. Preferably, each ofthe retaining members 1532 is associated with the base member 1530 bymeans of two angled rail members 1534. However, in alternateembodiments, one, three or more members 1534 may be used to associateeach retaining member 1532 with the base member 1530.

[0272] Further, each retaining member 1532 preferably defines a contactsurface 1533 and a channel 1536 to capture and retain the mountingmember 1522 on the syringe 1512. In addition, the retaining members 1532are preferably associated with one another by means of two rail members1538. Once again, in alternate embodiments, one, three or more railmembers 1538 may be used to associate the retaining members 1532 withone another.

[0273] To install the syringe 1512 on the syringe interface 1514, thesyringe 1512 is moved axially (in the direction of Arrow A in FIG. 40A)into the space defined between the retaining members 1532. When theflange 1524 on the syringe 1512 engages the contact surfaces 1533 on theretaining members 1532, the retaining members 1532 are urged toward thebase member 1530 along the rail members 1534. Because the rail members1534 are angled in toward the center of the base member 1530, the railmembers 1534 operate to cause the retaining members 1532 to move towardeach other along the rail members 1538 and to “collapse” around the rearend 1520 of the syringe 1512. As the retaining members 1532 collapse onthe syringe 1512, the retaining members 1532 cooperate to capture themounting member 1522 within the channels 1536 to securely engage thesyringe 1512 with the syringe interface 1514.

[0274] Any suitable type of locking mechanism (not shown), as is knownin the art, may be used to secure the retaining members 1532 together toretain the syringe 1512 within the syringe interface 1514. To remove thesyringe 1512 from the syringe interface 1514, the lock must first beunlocked and the retaining members 1532 moved apart (e.g., by hand or bymeans of a lever or any other suitable art-recognized manipulativedevice) to free the mounting member 1522 from the channels 1536.

[0275] Another embodiment of the syringe interface and syringe system1600 is shown in FIGS. 41A-41D. The system 1600 includes a syringe 1512and a syringe interface 1614. As best shown in FIGS. 41B and 41C, thesyringe interface 1614 is in an “open” position ready to accept thesyringe 1512. The syringe interface 1614 includes a base member 1630 andtwo cooperating syringe-retaining members 1632. The retaining members1632 are preferably connected together and associated with the basemember 1630 by means of a pivot pin 1631 or other suitable mechanism(see FIG. 41D). In addition, the retaining members 1632 are associatedwith the base member 1630 by means of pins 1629 (see FIG. 41D) that areassociated with the retaining members 1632 and captured within slots1635 defined in the base member 1630.

[0276] Further, each retaining member 1632 preferably defines a channel1636 to capture and retain the mounting member 1522 on the syringe 1512.As best shown in FIGS. 41B and 41C, a spring pin 1637 (or other suitablelocking mechanism) is connected to one retaining member 1632 and achannel with a pin recess 1640 is defined in the other retaining member1632. In addition, two barrel guide rails 1639 are preferably defined inthe base member 1630.

[0277] To install the syringe 1512 on the syringe interface 1614, thesyringe 1512 is moved downwardly (in the direction of Arrow B in FIG.41B) into the space defined between the retaining members 1632. Thebarrel 1516 of the syringe 1512 is guided into position between theretaining members 1632 by the barrel guide rails 1639 in the base member1630. When the syringe barrel 1516 engages the pivot ends 1651 of theretaining members 1632 (see FIG. 41C), the retaining members 1632 areurged to collapse around the rear end 1520 of the syringe 1512. The pins1629, riding in slots 1635 defined in the base member 1630, direct andcontrol the arcuate motion of the retaining members 1632 into engagementaround the syringe 1512. As the retaining members 1632 collapse on thesyringe 1512, the retaining members 1632 cooperate to capture themounting member 1522 within the channels 1636 to securely engage thesyringe 1512 with the syringe interface 1614.

[0278] Further, when the retaining members 1632 collapse around thesyringe 1512, the spring pin 1637 runs along the channel and locks intothe pin recess 1640 to secure the syringe 1512 within the syringeinterface 1614. To remove the syringe 1512 from the syringe interface1614, the spring pin 1637 must be removed from the pin recess 1640 tounlock the retaining members 1632 and the retaining members 1632 moved(e.g., by hand or by any suitable lever means) from engagement with thesyringe 1512. At this point, the syringe 1512 can be removed by eithermoving the syringe 1512 upwardly (in the opposite direction of Arrow B)or axially (in the direction of Arrow C in FIG. 41B).

[0279] FIGS. 42A-42D illustrate an alternate embodiment 1700 of thesyringe interface and syringe system 1600 shown in FIGS. 41A-41D. Thesystem 1700 includes a syringe 1512 and a syringe interface 1714. Thesyringe interface 1714, as best shown in FIGS. 42C and 42D, differs fromthe syringe interface 1614 in FIGS. 41A-41D in that the retainingmembers 1732 include pivot ends 1751 located at the ends of theretaining members 1732 remote from the pivot pin 1731. Further, theretaining members 1732 are preferably spring-biased in the “closed” or“engaged” position, as best shown in FIG. 42D, to retain the syringe1512 within the syringe interface 1714.

[0280] To install the syringe 1512 on the syringe interface 1714, thesyringe 1512 is moved downwardly (in the direction of Arrow D in FIG.42B) into engagement with the retaining members 1732. When the syringebarrel 1516 engages the pivot ends 1751 of the retaining members 1732,the retaining members 1732 are urged apart against the spring force toallow the syringe barrel 1516 to pass between the pivot ends 1751 andinto the space defined between the retaining members 1732. The syringemounting member 1522 is guided by the channels 1736 defined in theretaining members 1732 to correctly position the syringe 1512 within thesyringe interface 1714. Once the syringe 1512 passes the pivot ends1751, the retaining members 1732 are urged by the spring force tocollapse around the rear end 1520 of the syringe 1512. The pins 1729,riding in slots 1735 defined in the base member 1730, direct and controlthe arcuate motion of the retaining members 1732 into engagement aroundthe syringe 1512. As the retaining members 1732 collapse on the syringe1512, the retaining members 1732 cooperate to capture the mountingmember 1522 within the channels 1736 to securely engage the syringe 1512within the syringe interface 1714.

[0281] To remove the syringe 1512 from the syringe interface 1714, thesyringe 1512 is moved upwardly (in the opposite direction of Arrow D)against the pivot ends 1751 of the retaining members 1732. When theupward force on the syringe 1512 overcomes the spring force holding theretaining members 1732 together, the retaining members 1732 will moveapart and allow the syringe 1512 to slide free from the syringeinterface 1714.

[0282] FIGS. 43A-43I illustrate another alternate embodiment 1800 of thesyringe interface and syringe systems 1600, 1700 shown in FIGS. 41A-42D.The system 1800 includes a syringe 1512 and a syringe interface 1814.The syringe interface 1814, as best shown in FIGS. 43B and 43H, differsfrom the syringe interfaces 1614, 1714 in FIGS. 41A-42D in that theretaining members 1832 include extension members 1855 and chamfers 1857.The extension members 1855 preferably are manipulated to move theretaining members 1832 to an open position (i.e., against the springforce holding the retaining members 1832 in the closed position). Thechamfers 1857 are operably engaged by the inclined surface 1526 of themounting member 1522 of the syringe 1512 to open the retaining members1832 and allow the syringe 1512 to be axially installed (in thedirection of Arrow E in FIG. 43C) on the syringe interface 1814. Theremaining structure of the syringe interface 1814 is substantiallysimilar or identical to the structure of the syringe interface 1714described above.

[0283] As best shown in FIG. 43E, the syringe 1512 can be installed andremoved from the syringe interface 1814 in substantially the same manneras described above with respect to FIGS. 42A-42D. In addition, however,as best shown in FIGS. 43A, 43C, 43F and 43G, the syringe 1512 can beaxially installed and removed from the syringe interface 1814.Therefore, the syringe interface 1814 accommodates two methods ofinstalling/removing the syringe 1512.

[0284] To axially install the syringe 1512, the syringe 1512 is insertedinto the syringe interface 1814 until the mounting member 1522 engagesthe retaining members 1832. The inclined surface 1526 of the mountingmember 1522 engages the chamfers 1857 on the retaining members 1832,thereby forcing the retaining members 1832 apart against the springforce. After the mounting member 1522 clears the chamfered area, theretaining members 1832 collapse around and capture the mounting member1522 within the channels 1836 to secure the syringe 1512 to the syringeinterface 1814.

[0285] To axially remove the syringe 1512, the extension members 1855 ofthe retaining members 1832 may be manipulated (i.e., pressed together)to overcome the spring force and urge apart the retaining members 1832.When the retaining members 1832 have moved apart to such an extent thatthe mounting member 1522 of the syringe 1512 is cleared from engagementwithin the channels 1836, the syringe 1512 may be axially removed (inthe direction opposite from Arrow E) from the syringe interface 1814.

[0286]FIGS. 44A and 44B illustrate a first, slightly altered embodimentof the syringe interface 1814 shown in FIGS. 43A-43I incorporated in ormounted on an injector head. The functionality of the syringe interface1914 is substantially similar or identical to that described above withrespect to the syringe interface 1814.

[0287]FIGS. 45A and 45B illustrate a second, slightly altered embodimentof the syringe interface 1814 shown in FIGS. 43A-43I incorporated in ormounted on an injector head. The functionality of the syringe interface2014 is substantially similar or identical to that described above withrespect to the syringe interface 1814.

[0288] FIGS. 46A-46D illustrate a first preferred embodiment of afront-loading syringe interface and syringe system 2100 in accordancewith the present invention. The system 2100 includes a syringe 1512 anda syringe interface 2114. As best shown in FIG. 46A, the syringeinterface 2114 comprises a flexible, retaining ring 2150 disposedbetween a rear plate 2152 and a front plate 2154. The retaining ring2150 defines a rear ledge 2160 that is adapted to engage the mountingmember 1522 of the syringe 1512 when the syringe 1512 is installed inthe syringe interface 2114.

[0289] The ring 2150 comprises at least one, but preferably two, releasemembers 2156 and at least one, but preferably two, protrusion members2158. Further, the ring 2150 is preferably elliptical in shape to enableengagement with and disengagement from the mounting member 1522 of thesyringe 1512, as described in more detail below. As best shown in FIGS.46B-46D, the release members 2156 protrude from the rear and frontplates 2152, 2154 for manipulation by, for example, an operator torelease the syringe 1512 from the syringe interface 2114. Further, theprotrusion members 2158 are captured by and slide within channels (notshown) defined in the rear surface (not shown) of the front plate 2154to allow removal of the syringe 1512 from the syringe interface 2114when only one release member 2156, instead of both release members 2156,can be manipulated. (The channels are described below with respect tothe alternate embodiment of FIGS. 47A-47F and are shown in FIG. 47E.)

[0290] To install the syringe 1512 on the syringe interface 2114, thesyringe 1512 is moved axially (in the direction of Arrow F in FIG. 46C)into engagement with the syringe interface 2114. When the mountingmember 1522 engages the retaining ring 2150, the mounting member 1522urges the flexible, elliptically-shaped ring 2150 into a morecircularly-shaped configuration, thereby allowing the mounting member1522 to move pass the ring 2150. After the mounting member passes thering 2150, the ring 2150 returns to its original shape, therebycapturing the mounting member 1522 behind the rear ledge 2160 thereofand securing the syringe 1512 to the syringe interface 2114.

[0291] The protrusion members 2158 and the channels (not shown) areprovided to control/constrain the motion of the retaining ring 2150during syringe installation and removal. Specifically, the motion of thering 2150 during syringe installation and removal (i.e., fromsubstantially elliptical to substantially circular, and back) isdirected and controlled by the protrusion members 2158 being able toslide within the channels. Consequently, regardless of the orientationof the syringe 1512 during initial engagement with the retaining ring2150, the syringe force acting on the ring 2150 and the resulting motionof the ring 2150 is directed to and constrained by the protrusionmembers 2158 and the channels.

[0292] To remove the syringe 1512 from the syringe interface 2114, oneor both of the release members 2156 may be pressed inward (i.e., towardthe center of the syringe interface 2114), thereby forcing the ring 2150from engagement with the mounting member 1522 of the syringe 1512. Whenthe release member(s) 2156 is activated, the syringe 1512 may be graspedand moved axially (in the direction opposite from Arrow F in FIG. 46C)to remove the syringe 1512 from the syringe interface 2114.

[0293] When the release members 2156 are activated, the protrusionmembers 2158 slide within the channels (not shown) to direct the motionof the ring 2150 from a generally elliptical configuration to agenerally circular configuration to disengage the mounting member 1522from the rear ledge 2160 of the ring 2150.

[0294] As can be appreciated, the present embodiment permits a syringe1512 to be installed on a syringe interface 2114 with a simple,one-step, axial motion. To remove the syringe 1512, one or both of therelease members 2156 may be depressed and the syringe 1512 is simplyremoved axially from the syringe interface 2114.

[0295] FIGS. 47A-47F illustrate an alternate embodiment 2200 of thesystem 2100 shown in FIGS. 46A-46D. The system 2200 is substantiallysimilar or identical in structure and function to the system 2100described above in FIGS. 46A-46D, except that the release members 2256are substantially enlarged for easier and simpler manipulation.

[0296] As discussed above with respect to FIGS. 46A-46D, FIG. 47Eillustrates the channels 2270 formed in the front plate 2254 and theprotrusion members 2258 captured within the channels 2270.

[0297] FIGS. 48A-48C illustrate still another embodiment of afront-loading syringe interface and syringe system 2300 in accordancewith the present invention. The system 2300 includes a syringe 2312 anda syringe interface 2314. Unlike the syringe 1512 discussed anddescribed above with respect to the other embodiments of the syringeinterface and syringe system of the present invention illustrated inFIGS. 40A-47F, the syringe 2312 preferably comprises (in addition to theother components of syringe 1512) two notches 2327 defined in the rearthereof. Alternately, one, three or more notches 2327 may be defined inthe syringe 2312.

[0298] The syringe interface 2314 preferably comprises a base member2360 and a collet member 2362 rotatably mounted in the base member 2360.As described in more detail below, the base member 2360 preferablycomprises two dowel pins 2364 inserted therein. The collet member 2362comprises a plurality of segmented members or tangs 2368 formed therein,a helical track 2370 defined in a rear end thereof and at least twoposts 2372 operable to engage the notches 2327 in the syringe 2312.Preferably, for reasons described below, small detents 2374 may beformed at suitable locations within (e.g., at or adjacent to terminalends of) the helical track 2370. The collet member 2362 is held withinthe base member 2360 by means of the dowel pins 2364, which are capturedby and ride within the helical track 2370 in the collet member 2362.

[0299] To install the syringe 2312 on the syringe interface 2314, thenotches 2327 on the syringe 2312 are aligned with the posts 2372 on thecollet member 2362 and the syringe 2312 is inserted axially (in thedirection of Arrow G in FIG. 48B) into the collet member 2362 until thenotches 2327 engage the posts 2372. The syringe 2312 is then rotated(preferably in a clock-wise direction according to Arrow H in FIG. 48Band approximately 90°) relative to the initial syringe position tocomplete the installation. As the syringe 2312 is rotated, theengagement between the posts 2372 on the collet member 2362 and thenotches 2327 on the syringe 2312 cause the collet member 2362 to rotatewith the syringe 2312 within the base member 2360.

[0300] As the collet member 2362 rotates with the syringe 2312, thedowel pins 2364 riding within the helical track 2370 cause the colletmember 2362 to be pulled into the base member 2360. As the collet member2362 is pulled into the base member 2360, each tang 2368 is urged by theinclined surface 2365 of the base member 2360 into engagement with themounting member 2322 of the syringe 2312, thereby securing the syringe2312 within the syringe interface 2314. As can be appreciated, the “postand notch” engagement prevents syringe rotation relative to the colletmember 2362 and the “tang and mounting member” engagement prevents axialsyringe translation.

[0301] When the syringe 2312 (and collet member 2362) are fully rotatedinto place in the base member 2360, the dowel pins 2364 snap into placein the small detents 2374 to provide the operator with a tactile, andpossibly audible, feedback that the syringe 2312 is completely andsecurely installed in the syringe interface 2314.

[0302] To remove the syringe 2312 from the syringe interface 2314, thesyringe 2312 (and collet member 2362) is rotated (preferably in acounter-clockwise direction opposite from the direction of Arrow H)within the base member 2360. To initiate the rotation, sufficient forcemust be applied to the syringe 2312 (and collet member 2362) to causethe dowel pins 2364 to escape the detents 2374 and ride along thehelical track 2370. The syringe 2312 is then rotated until the dowelpins 2364 snap into place in the detents 2374 at the opposite end of thehelical track 2370. (The tactile (and possibly audible) feedback of thepins 2364 snapping into place will alert the operator that the syringe2312 may be removed from the collet member 2362.) As the collet member2362 rotates out of the “closed” position within the base member 2360,the tangs 2368 release the mounting member 2322 of the syringe 2312 andthe syringe 2312 may be removed axially (in the opposite direction ofArrow G) from the syringe interface 2314.

[0303] FIGS. 49A-49F illustrate another embodiment of an injector pistonand syringe plunger interface system 2400 of the present invention. Thesystem 2400 may be incorporated in the syringe interface and syringesystems described above. The system 2400 comprises an injector piston2402 having a piston head 2410 and a syringe plunger 2404 preferablycomprising a plunger base 2406 and a plunger cover 2408. As best shownin FIG. 49F, the plunger base 2406 and the plunger cover 2408 (which maybe formed of rubber) are preferably interconnected by means of amechanical connection.

[0304] As described below, the piston head 2410 and the plunger base2406 preferably engage one another by means of a bayonet-type,interlocking mechanism. As in know in the art, the piston 2402 ispreferably disposed within an injector (not shown) and the plunger 2404is preferably disposed within a syringe, such as the syringes 1512, 2312described above.

[0305] The piston head 2410 preferably comprises a pair of extendingflanges 2412 and, as best shown in FIG. 49E, the plunger base 2406preferably comprises a pair of retaining flanges 2414 separated bychannels 2416. To connect the piston 2402 and the plunger 2404, theextending flanges 2412 on the piston head 2410 are inserted along thechannels 2416 into the plunger 2404. When the extending flanges 2412clear the retaining flanges 2414, which is preferably indicated by theflange 2427 on the piston 2402 engaging the contact surface 2430 on theplunger 2404, either the piston 2402 or the plunger 2404 is rotated tocause the retaining flanges 2414 to be captured behind the extendingflanges 2412. To disconnect the piston 2402 from the plunger 2404, thereverse steps are preferably taken by the operator.

[0306] As can be appreciated by one skilled in the art, the piston 2402and the plunger 2404 may be engaged by translating and rotating theplunger 2404 (disposed within a syringe) into engagement with the piston2402 (disposed within an injector), or vice-versa. Alternately, thetranslational and rotational motions can be alternated between theplunger 2404 and the piston 2402 to interconnect the two members.

[0307]FIGS. 50A and 50B illustrate another embodiment of an injectorpiston and syringe plunger interface system 2500 of the presentinvention. The system 2500 preferably comprises a piston 2502 and aplunger 2504. The plunger 2504 is preferably configured as shown anddescribed above with respect to FIGS. 49A-49F. The piston 2502preferably comprises a piston head 2510 having a collet-type mechanism2530. The collet 2530 is preferably comprised of a plurality of flexiblesegment members or tangs 2534.

[0308] To connect the piston 2502 and the plunger 2504, the colletmechanism 2530 is inserted into the plunger 2504. When the tangs 2534pass the plunger undercut 2536 (as best shown in FIG. 50B), preferably arod or pin member (not shown) is driven through the center of the colletmechanism 2530 to radially force apart the tangs 2534 into lockingengagement with the plunger undercut 2536. To disconnect the piston 2502from the plunger 2504, the rod or pin member (not shown) is retractedfrom the center of the collet mechanism 2530, thereby causing the tangs2534 to disengage the plunger undercut 2536.

[0309] Due to the symmetrical nature of the collet mechanism 2530, noparticular alignment between the piston 2502 and the plunger 2504 isrequired for the piston 2502 and the plunger 2504 to engage and/ordisengage one another. This feature simplifies the installation andremoval of a syringe from a syringe interface.

[0310] As can be appreciated by one skilled in the art, the piston 2502and the plunger 2504 may be engaged by translating the plunger 2504(disposed within a syringe) into engagement with the piston 2502(disposed within an injector), or vice-versa.

[0311] FIGS. 51A-51C illustrate an alternate embodiment 2600 of theinjector piston and syringe plunger interface system 2500 shown in FIGS.50A and 50B. The structure and function of the system 2600 issubstantially similar or identical to the system 2500 shown in FIGS. 50Aand 50B, except that the collect mechanism 2630 is configured to becomplementary in shape to the plunger cover 2608 to support the plungercover 2608 during an injection procedure and to provide, for example,fluid pressure monitoring through the plunger 2604, as described in U.S.Pat. No. 5,808,203, the contents of which are hereby incorporated byreference.

[0312] FIGS. 52A-52C illustrate still another embodiment of an injectorpiston and syringe plunger interface system 2700 of the presentinvention. The system 2700 comprises a piston 2702 and a plunger cover2708. In contrast to the above embodiments, a plunger base is notpresent in the plunger 2704. Rather, the piston head 2710 is configuredto be complementary in shape to the plunger cover 2708 to support theplunger cover 2708 during a fluid injection.

[0313] Preferably, as best shown in FIG. 52A, the piston 2702 comprisesa base member 2760, a sleeve 2762, a segmented flap member 2764 and apiston cap 2766. During forward movement of the piston 2702 (e.g.,during a fluid injection), the piston 2702 preferably contacts and movesthe plunger cover 2708 without connectively engaging or locking thereto.Upon retraction of the piston 2702 (i.e., base member 2760, flap member2764 and cap 2766), the sleeve 2762 moves (in the direction of Arrow Iin FIG. 52B) into contact with the segmented flap member 2764 and urgesthe flaps 2765 radially outward into engagement with an undercut 2767formed in the plunger cover 2708 (as best shown in FIG. 52C) to connectthe piston 2702 and plunger cover 2708 together. Retraction of thepiston 2702 and plunger cover 2708 together is useful, for example, inaspirating fluid into a syringe for subsequent injection into a patient.

[0314] FIGS. 53A-53D illustrate an alternate embodiment 2800 of theinjector piston and syringe plunger interface systems 2600, 2700 shownin FIGS. 51A-51C and 52A-52C. The function of the system 2800 issubstantially similar or identical to that of the systems 2600, 2700,but there are different structural components that are explained below.

[0315] As best shown in FIGS. 53C and 53D, the collet mechanism 2830 isacted upon by an actuator 2870 disposed within the piston 2802 to urgethe tangs 2834 radially outward into engagement with an undercut 2836formed on the plunger cover 2808 to interconnect the piston 2802 and theplunger cover 2808. The collet mechanism preferably includes springretention members 2872, such as O-rings, to hold the tangs 2834 togetherand to spring-bias the tangs in a “disengage” position.

[0316]FIGS. 54A and 54B illustrate a current syringe plunger 2980, whichcomprises a plunger base 2984 and a mechanically-connected plunger cover2982.

[0317]FIGS. 54C and 54D illustrate an embodiment of the plunger 3080 ofthe present invention. The plunger 3080 comprises a plunger cover 3082having a larger syringe contact region (than the plunger cover 2982shown in FIGS. 54A and 54B) and a least three sealing elements 3083. Theplunger base 3084 comprises at least two flexible, piston-retentionmembers 3085, as shown and described in PCT Publication No. WO 98/20920,the contents of which are hereby incorporated by reference. The plungercover 3082 is preferably mechanically connected to the plunger base3084, as best shown in FIG. 54D.

[0318]FIGS. 54E and 54F illustrate another embodiment of the plunger3180 of the present invention. The plunger cover 3182 is substantiallysimilar or identical to the plunger cover 2982 shown in FIGS. 54A and54B. The plunger base 3184 comprises at least two flexible,piston-retention members 3185.

[0319]FIGS. 54G and 54H illustrate an alternate embodiment of theplunger 3280 of the present invention. The plunger cover 3282 issubstantially similar or identical to the plunger cover 2982 shown inFIGS. 54A and 54B. The plunger base 3284 comprises a longer base regionand at least two flexible, piston-retention members 3285.

[0320] As can be appreciated, the plungers 2980, 3080, 3180, 3280 shownand described above may be incorporated in the syringes 1512, 2312described herein.

[0321] The most preferred embodiments of the present invention will bedescribed in connection with FIGS. 55-109. Of these drawings, FIGS.55-78 concern the second preferred embodiment of the syringeinterface/release mechanism that releasably secures the syringe to theinjector housing. FIG. 79 illustrates the efficacy of the flangeassembly associated with the syringe of a related art medical injectorassembly, which applies equally to the function of the flange on thesyringe of the present invention. FIGS. 80-109 illustrate the firstpreferred embodiment of the injector piston and syringe plungerinterface system/assembly of the present invention that cooperates toaxially move the plunger within the syringe.

[0322] Among other features (as illustrated in FIGS. 55-57), the secondpreferred embodiment of the syringe interface of the present inventionencompasses a release mechanism 4010 for connecting a syringe 4012 to aninjector 4014.

[0323] Specifically, the second preferred embodiment of the presentinvention provides a mechanism by which a syringe 4012 may be connectedquickly to an injector 4014 without the requirement (present in theprior art) for any particular orientation of the syringe 4012 to theinjector 4014 during installation. The release/connector mechanism 4010of the present invention also provides an audible “click” when thesyringe 4012 fully engages the connector/release mechanism 4010.Additionally, the present invention provides an audible “click” when thesyringe 4012 has been disengaged from the release/connector mechanism4010. The audible “click” for connection and removal of the syringe 4012from the release/connector mechanism 4010 is a particularly usefulfeature because it provides the operator with an audible confirmation ofproper engagement and disengagement of the syringe 4012 from therelease/connector mechanism 4010.

[0324]FIG. 55 illustrates generally the syringe interface/releasemechanism 4010 (hereinafter, release or connector mechanism 4010, forbrevity) of the present invention. A rear surface 4016 of releasemechanism 4010 attaches to a front surface 4018 of injector 4014. Afront surface 4020 of release mechanism 4010 is adapted to receive arear end 4022 of syringe 4012.

[0325] Release mechanism 4010 may be affixed to front surface 4018 ofinjector 4014 in any suitable manner known to those skilled in the art.For example, release mechanism 4010 may be attached by means of screws(not shown) extending from the front surface 4018 of injector 4014. Aswould be appreciated by those skilled in the art, any suitablealternative connection may be employed. For example, release mechanism4010 may be affixed by means of tabs or other suitable connectors thatpermit release mechanism 4010 to be removed from injector 4014 forcleaning of the components contained therein. In addition, releasemechanism 4010 may be adapted to mount to conventional injectors toallow syringes of the present invention to be used therewith.

[0326] The second preferred embodiment of the syringe interface/releasemechanism 4010, which is illustrated in FIGS. 55-78, includes aconnector housing 4024. Connector housing 4024 contains within it atleast two elements that facilitate connection of syringe 4012 toinjector 4014. The first of the two elements is a flex ring 4026, whichis disposed within release mechanism 4010 near front end 4020. Thesecond of the two elements is a rotating ring 4028, which is disposedwithin release mechanism 4010 near rear end 4016. Flex ring 4026 androtating ring 4028 are adapted to cooperate with one another, asdescribed in greater detail below, to permit connection and release ofsyringe 4012 to and from release mechanism 4010 (and, accordingly, toand from injector 4014).

[0327]FIGS. 56 and 57 illustrate release mechanism 4010 and syringe 4012in an exploded perspective view to facilitate an understanding of thisaspect of the present invention. Syringe 4012 includes a cylindricalbody 4030 with a tapering conical portion 4032 at a front end 4034.Conical portion 4032 is integrally connected to a discharge end 4036.Discharge end 4036 is provided with a luer lock 4038 that may beconnected to a tube (not shown) that is connected ultimately to thepatient (also not shown).

[0328] As would be understood by those skilled in the art, syringe 4012may be made from any suitable material, such as a polymeric material.Specifically, syringe 4012 may be made of PET (polyethyleneterephthalate). Alternatively, syringe 4012 may be constructed frompolymethylpentene (which is made by Mitsui Plastics under the tradename“TPX”).

[0329] At rear end 4022, syringe 4012 includes a flange 4042, which,when syringe 4012 is connected to release mechanism 4010, helps toprevent contrast medium that may leak from, for example, discharge end4036 or luer lock 4038 from entering release/connector mechanism 4010.FIG. 79, which illustrates a related art syringe, helps to illustratethe advantages provided by flange 4042 on syringe 4012.

[0330] As shown in FIGS. 55-57, a ridge 4044 is integrally formed onsyringe 4012 behind flange 4042 toward rear end 4022 of syringe 4012.Alternately, as shown in FIG. 123, the ridge may be segmented into twoor more sections 4044 a instead of a single continuous member. However,the sections 4044 a must collectively provide sufficient surface areaand strength to retain the syringe 4012 on the injector 4014.

[0331] As shown in FIGS. 55-57, ridge 4044 includes two parts, a slopingsection 4046 and a shoulder section 4048 that is essentiallyperpendicular to the exterior surface of cylindrical body 4030. At leastone, and preferably two or more, extending tabs or projections 4050 areprovided at rear end 4022 of syringe 4012. Tabs 4050 engage grooves 4052provided in ring 4028. Alternatively, as would be understood by thoseskilled in the art, slots, recesses or divots, etc. could be provided inrear end 4022 of syringe 4012 and tabs or projections could be providedon the interior surface of rotating ring 4028.

[0332] In addition, to mount conventional syringes on the syringeinterface 4010 of the present invention, a syringe adapter incorporatingthe structural components (e.g., ridge 4044, tabs 4050 and/or flange4042) of the rear end 4022 of syringe 4012 could be fashioned to fit toa conventional syringe for mounting on the injector of the presentinvention. Of course, to properly engage the conventional syringe, theadapter would preferably include structural components complementary tothe mounting elements of the conventional syringe.

[0333] Release/connector mechanism 4010 includes a front plate 4054 anda rear plate 4056. Front plate 4054 and rear plate 4056 are preferablyconstructed of aluminum coated with a fluoropolymer (such as Tufram™,which is the product name of a fluoropolymer manufactured by the GeneralMagna Plate Company). The fluoropolymer coating provides improvedresistance to wear and also provides lubricity to the exterior surfacesof front plate 4054 and rear plate 4056. Lubricity is particularlyadvantageous because, when contrast medium crystallizes on the exteriorsurface of front plate 4054 or rear plate 4056, it easily flakes off ofthe surface when the surface is coated with the fluoropolymer. Ofcourse, any suitable alternative coating material may be used on theexterior surface of front plate 4054 or rear plate 4056.

[0334] In still another alternative embodiment, a coating may not needto be applied to the surface of front plate 4054 or rear plate 4056 ifeither plate is made of a suitable material. For example, if front plate4054 and rear plate 4056 are constructed of a high density plastic (anacetyl copolymer, for example) the material itself may provide the sameresistance to caking of contrast media as does the fluoropolymer coatingon aluminum.

[0335] As shown in FIGS. 56 and 57, front plate 4054 includes a hole4058 therethrough. A lip 4060 extends around the periphery of hole 4058through front plate 4054. In one preferred embodiment, when syringe 4012engages release/connector mechanism 4010, flange 4042 and lip 4060 matewith one another to minimize any leaked contrast medium from enteringthe interior of connector mechanism 4010 through hole 4058. FIG. 72 isparticularly illustrative of the mating engagement between lip 4060 andflange 4042. Alternatively, syringe 4012 may be constructed so that itdoes not include flange 4042, as would be understood by those skilled inthe art. In addition, some alternative structure may be provided oneither syringe 4012 or front plate 4054 to minimize ingress of contrastmedium into the interior of release/connector mechanism 4010.

[0336] In the embodiment described and illustrated throughout FIGS.55-78, flange 4042 also serves an additional function as a mechanicalstop when it engages with front surface 4020 of front plate 4054.

[0337] Contrast medium of the type typically used within syringe 4012may interfere with the operation of connector/release mechanism 4010.Accordingly, it is advantageous to include some structure, such asflange 4042 (see FIG. 79), to minimize the ingress of contrast mediuminto the interior of connector mechanism 4010. However, it is believedthat connector/release mechanism 4010 will operate even if fouled withsome contrast medium, which is usually unavoidable.

[0338] Flex ring 4026 is a substantially elliptically-shaped member thatis disposed behind front plate 4054 of release/connector mechanism 4010.Flex ring 4026 may be made from an acetal copolymer or any othersuitable material. As best shown in FIGS. 66 and 67, flex ring 4026includes, on either side, a linear or flattened portion 4062 that isintegrally connected to two curved portions 4064. From approximately themidpoint of the curved portions 4064, posts 4066 extend toward rearplate 4056. As shown, flex ring 4026 includes a hole 4068 therethrough.As shown in FIG. 66, on a front side 4080 of flex ring 4026, a chamferedsurface 4082 is provided. As explained below, chamfered surface 4082facilitates insertion of rear end 4022 and ridge 4044 of syringe 4012therethrough.

[0339] In the embodiment illustrated in FIGS. 56 and 57, posts 4066extending rearward from flex ring 4026 are provided with bearings 4070.(Flex ring 4026 is illustrated in detail in FIGS. 66 and 67.) Bearings4070 preferably are composite bearings (for example, metal and plastic)having inner and outer races with roller bearings disposed therebetween.Alternatively, bearings 4070 may be plastic elements that surround posts4066 and rotate with respect thereto. Bearings 4070 engage grooves orcam tracks 4072 on rotating ring 4028. As would be appreciated by thoseskilled in the art, however, bearings are not required for the operationof release/connector mechanism 4010. FIG. 114 illustrates one alternateembodiment of the present invention where bearings 4070 are omitted,which simplifies construction of connector mechanism 4402 and,accordingly, reduces the cost of its manufacture.

[0340] Rotating ring 4028, which is disposed to the rear of flex ring4026 within housing 4024, includes two grooves or cam tracks 4072 on afront surface 4074 thereof. As best shown in FIGS. 61, 68 and 69, camtracks 4072 are shaped such that the outer surface 4074 increases indiameter along its arc from the closest point 4076 to the center ofrotating ring 4028 to the farthest point 4078 from the center of ring4028. Grooves 4072 engage posts 4066 through bearings 4070 and, whensyringe 4012 is rotated while engaging rotating ring 4028 (e.g., todisengage syringe 4012 from release/connector mechanism 4010), forceposts 4066 apart to stretch flex ring 4026 in a direction indicated byarrow 4084 in FIGS. 66 and 67. As shown, flex ring 4026 has a hole 4068through its center to accommodate rear end 4022 of syringe 4012 thereinor therethrough.

[0341] Rotating ring 4028, which is shown in detail in FIGS. 68 and 69,is disposed within an indentation or recess 4090 formed in front surface4088 of rear plate 4056. (Rear plate 4056 is shown in detail in FIGS. 70and 71.) Rear plate 4056 has a hole 4092 therethrough for accommodatingrear portion 4022 of syringe 4012. Rotating ring 4028 is disposed inindentation 4090 so that ring 4028 may freely rotate therein. Rear plate4056 has a rear surface 4094, which is illustrated in FIGS. 57 and 71.

[0342] As shown in FIGS. 57, 58 and 64, a rear surface 4096 of frontplate 4054 includes an indentation or recess 4098 that has essentiallythe same shape as flex ring 4026. As such, indentation 4098 includes twolinear or flattened portions 4100 and two curved portions 4102. (Seee.g., FIGS. 58 and 64.) Two notches 4104 in rear surface 4096 of frontplate 4054 are positioned at approximately the center point of curvedsections 4102. Notches 4104 accommodate posts 4066 and the associatedstructures that connect posts 4066 to flex ring 4026. Indentation 4098is shaped to be larger than flex ring 4026 and a distance 4106 betweennotches 4104 is greater than a distance 4108 between posts 4066 (seeFIGS. 66 and 67) in their relaxed state. Notches 4104 help to preventflex ring 4026 from rotating within housing 4024 and permit flex ring4026 to expand upon rotation of rotating ring 4028.

[0343] The operation of release/connector mechanism 4010 is illustratedin and described by reference to FIGS. 74-78 and 55-73.

[0344] As illustrated in FIGS. 74-76, rear end 4022 of syringe 4012 isinserted into connector housing 4024 through hole or interface 4058 infront plate 4054, in the direction indicated by arrow 4110. Flex ring4026 sits within indentation 4098 formed in rear surface 4096 of frontplate 4054 so that posts 4066 engage notches 4104. Therefore, wheninclined surface 4046 of ridge 4044 of syringe 4012 engages chamfers4082 on flex ring 4026, ridge 4044 pushes open flex ring 4026 indirection 4084 (shown in FIGS. 66 and 67) from its relaxed distance 4108(see FIG. 77) to its extended (or tensioned) distance 4106 (see FIGS. 58and 78). FIG. 75 is illustrative of this feature. Flex ring 4026 opensin the direction indicated by arrows 4112.

[0345] After ridges 4044 clear the rear edge of flex ring 4026, theelastic nature of flex ring 4026 causes flex ring 4026 to resume itsrelaxed state in the direction of arrows 4114, as illustrated in FIG.76. When flex ring 4026 resumes its relaxed state, the shoulder 4048 ofridge 4044 engages the rear edge of flex ring 4026. The syringe 4012 isthereby held in place by flex ring 4026 and cannot be axially removedfrom release/connector mechanism 4010. When flex ring 4026 resumes itsrelaxed state, it preferably provides an audible “click” to indicate tothe operator that the syringe 4012 has been installed on the injector.

[0346] Removal of syringe from release/connector mechanism 4010preferably requires that syringe 4012 be rotated ¼ turn or anapproximate one quarter turn, as described below. This operation isillustrated in and described by reference to FIGS. 77, 78 and 55-73.

[0347] As illustrated in FIGS. 60 and 73, once syringe 4012 has beenengaged by flex ring 4026, the two projections 4050 engage two ofgrooves 4052 in rotating ring 4028. FIG. 77 illustrates across-sectional view of the engagement of syringe 4012 and flex ring4026 (which is shown as an entirely elliptical structure forconvenience). (In alternate embodiments, one, three or more projections4050 may be provided on the syringe 4012.) As best shown in FIGS. 55-57,the projections 4050 are preferably triangular in shape, with a point ofthe “triangle” being directed first into engagement with the grooves4052 in rotating ring 4028. This design allows the projections 4050 toreadily align with and engage the respective grooves 4052 in therotating ring 4028 when the syringe 4012 is inserted into therelease/connector mechanism 4010, without the operator having to joggleor twist the syringe 4012 to seat the projections 4050.

[0348] As syringe 4012 is rotated, in a preferred embodiment,approximately one quarter turn in the counter-clockwise direction,projections 4050, which engage grooves 4052, force rotating ring 4028also to rotate approximately the same amount in the same direction.While the mechanism 4010 is preferably designed to release syringe 4012by means of a counter-clockwise rotation, it is specificallycontemplated that mechanism 4010 may be adapted to release syringe 4012by means of a clockwise rotation. (It should be noted that theone-quarter turn to which reference is made herein is not intended tomean exactly one quarter of a turn. The term “one quarter turn” is meantto indicate a turn that is about one quarter turn and preferably in arange from 45 to 90 degrees from the rest position of syringe 4012.Alternately, any suitable range of rotation may be used to facilitatedisengagement of the syringe 4012 from mechanism 4010.)

[0349] Because posts 4066 (with bearings 4070) of flex ring 4026 engageand ride along cam tracks 4072 on rotating ring 4028, the rotation ofring 4028 will urge flex ring 4026 from its relaxed (i.e., syringeengaged) state to its extended (i.e., syringe disengaged) state. Asposts 4066 travel along cam tracks 4072 from the inner-most position4076 to the outermost position 4078, flex ring 4026 is stretched fromthe relaxed distance 4108 to the extended distance 4106 (in thedirection of Arrows 4112), at which point the rear edge of flex ring4026 disengages the shoulder 4048 of syringe 4012. Consequently, thesyringe 4012 is disengaged and may be axially removed from flex ring4026 and mechanism 4010. When the syringe 4012 is removed from themechanism 4010, the spring force of the flex ring 4026 urges the posts4066 to travel along the cam tracks 4072 from the outer-most position4078 to the inner-most position 4076, thereby returning the flex ring4025 to its relaxed state for receipt of a new syringe. In addition,when the syringe 4012 is disengaged from the flex ring 4026, theoperator preferably hears a second audible “click” to indicate that thesyringe 4012 has been disengaged from the mechanism 4010 (and,accordingly, the injector).

[0350] A third preferred embodiment of the syringe interface/releasemechanism is shown in FIGS. 124 and 125. Because the third preferredembodiment is similar in function and structure to the second preferredembodiment illustrated in FIGS. 55-78, for ease of reference the samereference numerals have been used to identify the respective componentsthereof. The differences between the second and third preferredembodiments are discussed below. The third preferred embodiment shown inFIGS. 124 and 125 includes a pair of return springs 4091 to assist flexring 4026 and rotating ring 4028 to return to their rest state aftersyringe 4012 is released from release/connector mechanism 4010.(Optionally, bearings 4093 may be provided for springs 4091. Thesebearings may be retained in rear plate 4056 by pins (not shown) andformed of Delrin®.) In this embodiment, the return springs 4091 aredisposed between the rotating ring 4028 and the rear plate 4056.However, the return springs 4091 may be connected between rotating ring4028 and the front plate 4054 of housing 4024. The rotating ring 4028preferably includes a pair of projecting tabs 4095 to which the freeends 4097 of the springs 4091 are connected. As shown, the springs 4091preferably ride within and are constrained by a pair of complementaryshaped recesses 4099 formed in the rear plate 4056. The return springs4091 are preferably ¾″ constant force springs provided by AssociatedSpring Raymond. The return springs 4091 are especially useful inassisting the flex ring 4026 and the rotating ring 4028 to return totheir rest state if the elements of syringe interface/connectormechanism 4010 have become fouled with contrast media during the medicalprocedure (or over time after repeated use).

[0351] As discussed above, FIG. 79 illustrates the efficacy of flange4042 for preventing contrast media in syringe 4012 from entering asyringe interface and injector of the present invention.

[0352] The present invention also includes a construction for a firstpreferred embodiment of an injector piston and syringe plunger interfaceassembly 4200 for injector 4014 that engages a plunger within syringe4012 without regard to the orientation of syringe in release/connectormechanism 4010 or the orientation of the plunger within the syringe4012. FIGS. 80-109 are illustrative of piston/plunger assembly 4200 andits operation.

[0353] Piston/plunger assembly 4200 is positioned movably in an axialrelation to injector 4014 and syringe 4012. As shown in FIGS. 85 and 86,piston 4202 includes a rear end 4204 and a front end 4206. Piston 4202also includes an elongated shaft 4208 extending between rear end 4204and front end 4206. Rear end 4204 of piston 4202 is connected to a moveror motor drive train within injector 4014. The mover may be any type ofmover suitable for moving piston 4202 axially into and out from injector4014, including a motor and drive train combination.

[0354] As shown in FIGS. 80-82, a piston sleeve 4210 surrounds shaft4208 of piston 4202. Piston sleeve 4210 is freely movable with respectto piston 4202. In other words, piston sleeve 4210 is not connected topiston 4202. Piston sleeve 4210 is essentially a cylindrical tube with afront end 4212 and a rear end 4214. (See FIG. 87 for an enlarged detailof piston sleeve 4210.)

[0355] A collar 4216 is disposed at front end 4212 of piston sleeve4210. As shown in FIGS. 88-90, collar 4216 includes a hole 4218 throughwhich piston 4202 is disposed. An annular flange 4219 is provided on arear side 4220 of collar 4216 for engagement of front end 4212 of pistonsleeve 4210. A second annular flange 4222 is provided on a front surface4224 of collar 4216. Annular flange 4222 engages a plunger cap 4226,which is generally depicted in FIGS. 97-100.

[0356] Plunger cap 4226 has a base portion 4230 that extends outwardlyfrom a base thereof. (See FIGS. 97-100.) The base portion 4230 isconnected to a frusto-conical section 4232 that tapers inwardly toward acenterline of plunger cap 4226. An annular groove 4234 is provided inplunger cap 4226 near frusto-conical section 4232. Slots 4236 aredisposed within annular groove 4232 for retaining support ring grippers4238. A top portion 4240 of plunger cap 4226 extends upwardly fromannular groove 4234. Top portion 4240 is cone shaped and terminates in arounded tip 4242. As illustrated in FIG. 98, plunger cap 4226 isessentially a hollow body that defines an interior volume 4244.

[0357] Front end 4206 of piston 4202 extends into interior volume 4244of plunger cap 4226. As shown in FIGS. 107 and 108, front end 4206 ofpiston 4202 is connected to gripper expander 4246. Gripper expander 4246is connected to front end 4206 of piston 4202 by any suitable means suchas a screw (not shown) disposed through a hole 4248 that extends throughthe center of gripper expander 4246. (Detailed illustrations of gripperexpander 4246 are provided in FIGS. 91-93.) Gripper expander 4246 has atop surface 4250 and a bottom surface 4252. From top surface 4250,gripper expander 4246 tapers inwardly to form a frusto-conical section4254. A cylindrical section 4256 extends from frusto-conical section4254 to bottom surface 4252. When connected to front end 4206 of piston4202, gripper expander 4246 forms a T-shaped structure with piston 4202,as illustrated in FIGS. 107 and 108.

[0358] As illustrated in FIGS. 83, 84, 94-96, 107 and 108, support ringgrippers 4238 extend through the slots 4236 in annular groove 4234 ofplunger cap 4226. Support ring grippers 4238 are designed to extendoutwardly from annular groove 4234 when piston/plunger assembly 4200 ismoved in a rearward direction or retracted (into injector 4014). Asshown in FIGS. 94-96, support ring grippers 4238 have a body 4258 thatis L-shaped in cross-section. On an interior edge 4260, support ringgrippers 4238 are provided with a chamfer 4262 that engages withfrusto-conical surface 4254 on gripper expander 4246. When gripperexpander 4246 moves in the direction of injector 4014, which isindicated by arrows 4264 in FIG. 108, support ring grippers 4238 moveoutwardly from plunger cap 4226 in the direction of arrows 4266 (alsoshown in FIG. 108).

[0359] A rubber cover 4268 (which is shown in detail in FIGS. 105 and106) is usually assembled with syringe 4012 and is located therein.Movement of rubber cover 4268 causes the liquid contained in syringe4012 to be pushed out through the discharge end 4036 and into thepatient. Rubber cover 4268 includes a conically-shaped top 4270 with asubstantially cylindrical 4272 portion extending rearwardly therefrom.Cylindrical portion 4272 may include any number of ridges 4274 andgrooves 4276 that may be required for a particular application to assurethat the liquid does not pass by the plunger and leak out of the syringe4012 during, for example, an injection procedure.

[0360] The interior of rubber cover 4268 is hollow and, as a result, hasa conical inner surface 4278. In addition, at a bottom end 4280, a lip4282 is provided that defines a circular opening 4284 into the interiorof rubber cover 4268. Lip 4282 is designed to be engaged by a rubbercover support ring 4286.

[0361] Rubber cover support ring 4286, which is shown in detail in FIGS.101-104, is constructed of a suitable plastic material. Rubber coversupport ring 4286 engages lip 4282 on the interior of rubber cover 4268and provides additional rigidity to rubber cover 4268. Rubber coversupport ring 4286 includes an annular ring 4288 at a bottom portion 4290thereof. A groove 4292 is provided above annular ring 4288 forengagement of lip 4282 of rubber cover 4268. A frusto-conical section4294 extends upwardly from groove 4292 and mates within the interiorsurface 4278 of the rubber cover 4268. A hole 4296 extends throughrubber cover support ring 4286. The interior surface of rubber coversupport ring 4286 includes a lip 4298 with a chamfered surface 4300. Lip4298 serves as a location for engagement by support ring grippers 4238.

[0362] In an alternate embodiment of rubber cover 4268, rubber coversupport ring 4286 may be eliminated altogether. The alternate embodimentof the rubber cover, which is designated 4306, is illustrated in FIGS.110-113. Since rubber cover 4306 does not include rubber cover supportring 4286, rubber cover 4306 is thicker in cross-section than rubbercover 4268. So that grippers 4238 may engage rubber cover 4306 during atleast a retraction operation of injector 4014, rubber cover 4306includes a lip 4308 on an interior surface.

[0363] Rubber cover 4306 has essentially the same shape as rubber cover4286. Rubber cover 4306 includes a conically-shaped top portion 4310with a rounded tip 4312. At its lower end 4314, rubber cover 4306includes three ribs 4316 and two grooves 4318 positioned along acylindrical portion. The interior of rubber cover 4306 defines aninterior volume 4320 with tapered sides 4322. Rubber cover 4306 isthicker than rubber cover 4286 so that it has added strength and sealingcapabilities (i.e., to the interior of syringe 4012).

[0364] The operation of piston/plunger assembly 4200 will now bedescribed in connection with FIGS. 107-109. The operation ofpiston/plunger assembly 4200 does not differ substantially if rubbercover 4268 (together with rubber cover support ring 4286) or rubbercover 4306 are employed within syringe 4012.

[0365] When the operator of injector 4014 desires to advance or push thepiston/plunger assembly 4200 forward, he may push one of the buttons4302 on injector 4014 to actuate forward movement of piston 4202.Movement of piston 4202 in the forward direction pushes rubber cover4268 in the forward direction. Because forward movement of rubber cover4268 in the forward direction does not require any connection betweenpiston assembly 4202 and rubber cover 4268, the two are only in a matingengagement with one another. However, if the operator of injector wishesto retract or move rubber cover 4268 in the rearward direction,piston/plunger assembly 4200 must grab onto rubber cover 4268 to pull ittoward injector 4014.

[0366] To grab onto rubber cover 4268 (and its associated rubber coversupport ring 4286, where included), grippers 4238 extend outwardly tograb onto lip 4298 of rubber cover support ring 4286. If the alternativerubber cover 4306 is used, grippers 4238 engage lip 4308. The engagementof lip 4298 (or alternatively lip 4308) by grippers 4238 is describedbelow.

[0367] As mentioned above, piston sleeve 4210 is not connected to piston4202. Instead, it is freely moveably (in the axial direction) withrespect to piston 4202. Within injector 4014, there is an o-ring 4304that matingly engages the exterior surface of piston sleeve 4210. (SeeFIGS. 107 and 108.) Accordingly, when piston 4202 is withdrawn intoinjector 4014, piston sleeve 4210 experiences a frictional engagementwith o-ring 4304 that tends to hold piston sleeve 4210 in place. Inother words, ring 4304 biases piston sleeve 4210 in a forward directionwhen piston 4202 is retracted in a rearward direction.

[0368] Because piston 4202 is connected to gripper expander 4246, aspiston 4202 moves into injector 4014, so does gripper expander 4246.However, piston sleeve 4210, collar 4216, and plunger cap 4226, whichare the elements connected to one another, are biased in a forwarddirection by O-ring 4304. Accordingly, when actuated, piston 4202 andgripper expander 4246 move rearward in relation to piston sleeve 4210,collar 4216 and plunger cap 4226. Frusto-conical section 4254 of gripperexpander 4246 is then caused to engage chamfered regions 4262 to forcegrippers 4238 outwardly through slots 4236 in plunger cap 4226, as shownby Arrows 4266 in FIG. 108, and into engagement with lip 4298 (or lip4308) of support ring 4286. To hold grippers 4238 in place, a rubbersheath (not shown) may be placed over plunger cap 4226. The rubbersheath may also assist in preventing contrast medium from enteringplunger cap 4226 through slots 4236.

[0369] By this construction, then, rubber cover 4268 connectivelyengages piston 4202 only when piston 4202 is retracted or moved in arearward direction into or toward injector 4014. When stationary or whenmoving forward, rubber cover 4268 does not engage piston 4202 so thatsyringe 4012 may be easily disengaged from syringe interface 10.

[0370] As can be appreciated, the piston/plunger assembly 4200 of thepresent invention is preferably not orientation specific. That is,engagement between the piston 4202 and the plunger cover 4268 can occurwithout regard to the orientation of the plunger within the syringe 4012and/or the orientation of the plunger with respect to the piston 4202.In conjunction with suitable syringe interfaces of the presentinvention, injector and syringe systems are provided that do not requirean operator to orient the syringe in any particular manner with respectto the injector to mount the syringe thereon. The present invention, inat least one aspect, thereby improves and facilitates the mounting andinstallation of syringes on injectors.

[0371]FIG. 114 illustrates an alternate embodiment of therelease/connector mechanism 4402 of the present invention. Here, flexring 4026 does not include bearings 4070 around posts 4066. As mentionedabove, this simplifies the construction of connector mechanism 4402.Here, release/connector mechanism 4402 operates in the same manner asconnector mechanism 4010 except that posts 4066 engage cam tracks 4072directly. For convenience, screws 4404 are shown that hold front plate4054 to rear plate 4056.

[0372]FIG. 115 illustrates another embodiment of the syringeinterface/connector mechanism 4406 of the present invention. Here,rotating ring 4028 has been eliminated altogether. In this embodiment,grooves 4408 are provided on an inner surface of flex ring 4410 forengagement with projections 4412 on syringe 4414 (see FIG. 117). Posts4416 extend from upper and lower positions on flex ring 4410 and engagegrooves 4418 in back plate 4420 (or, alternatively, in the front plate(not shown)). When syringe 4414, which is illustrated in cross-sectionin FIG. 117, is rotated (preferably in a counter-clockwise direction),projections 4412 rotate flex ring 4410 so that posts 4416 travel ingrooves 4418 to stretch flex ring 4410 and release syringe 4414. For thebarrel projections 4412 to engage grooves 4408, the projections 4412 arepositioned between ridge 4044 and flange 4042. So that the differencesbetween the two alternative designs may be evaluated, syringe 4414 isillustrated adjacent syringe 4012 (see FIGS. 116 and 117).

[0373]FIG. 118 illustrates three alternate embodiments of the differentshapes for grooves for rotating ring 4028 or flex ring 4410. It shouldbe noted that the different shapes for grooves 4052 may be used with anyalternative embodiment of rotating ring or flex ring described herein.First, in embodiment #1, grooves 4052, which are the same as thosedepicted in FIG. 59, are illustrated. In embodiment #1, grooves 4052 aresemi-cylindrical indentations on the inner surface of rotating ring4028. Embodiment #2 illustrates grooves 4052′ that are triangularlyshaped. Embodiment #3 illustrates that grooves 4052″ are U-shaped. Thoseskilled in the art should readily recognize that grooves 4052, 4052′,4052″ may be of any suitable shape to engage projections 4050 or theirequivalent.

[0374] One possible disadvantage of the previously described embodimentsof the syringe interface/connector mechanism of the present invention ismade apparent by the illustrations in FIGS. 77 and 78. There, it can beobserved that flex ring 4026 engages ridge 4044 on syringe 4012 at onlytwo locations 4400 around the periphery of syringe 4012. While thisworks in most instances to hold syringe 4012 in place, there are someinstances where high pressure must be applied to inject contrast mediumin syringe 4012 into a patient. Where high pressure (e.g., pressure ator above 1000 p.s.i.) is applied, the two regions 4400 may not provideenough contact area with ridge 4044 to hold syringe 4012 securely inrelease/connector mechanism 4010. In these instances, it is preferredthat flex ring 4026 contact most, if not all, of ridge 4044 around thecircumference of syringe 4012.

[0375]FIG. 119 illustrates an embodiment of the release/connectormechanism 4440 of the present invention that offers a flexible ring 4450that is circularly shaped to engage a significant portion of ridge 4044along the periphery of syringe 4012. Flexible ring 4450 is nearly acomplete circle with an inner diameter, in a relaxed state, that is justlarger than the outer circumference of syringe body 4030. Flexible ring4450 includes two posts thereon, post 4452 that engages a hole 4456 in agroove 4460 in front plate 4462 and another post 4454 that fits into ahole 4458 in rotating ring 4464. Rotating ring 4464 is nested in anindentation (not shown) in back plate 4466. Screws 4468 may be used toassemble release/connector mechanism 4440.

[0376] As with other embodiments, syringe 4012 is inserted through hole4470 in front plate 4462. When ridge 4044 of syringe 4012 clears flexring 4450, flex ring 4450 snaps into place around syringe 4012 andprovides an audible “click”. When in place, projections 4050 on syringe4012 engage grooves 4472 on the interior surface of rotating ring 4464.

[0377] To disengage syringe 4012 from release/connector mechanism 4440,syringe 4012 is rotated approximately one-quarter turn. The rotation ofsyringe 4012 causes rotating ring 4464 to turn in the direction of arrow4474. As rotating ring 4464 turns, pressure is applied to post 4454 tocause flex ring 4450 to enter a tensioned state where it has a largerinner diameter. When a sufficient amount of force has been applied toflex ring 4450, it releases syringe 4012 and provides an audible “click”upon doing so.

[0378] In the previous embodiments, the flex ring has been shown as asingle piece construction. It is possible, however, that flex ring couldbe constructed from several pieces that are connected in a manner to oneanother or to the housing for the release/connector mechanism so thatthe separate elements have a relaxed and a tensioned state (as does thesingle piece construction).

[0379] One possible embodiment of a two-piece “flex ring” is illustratedin FIG. 120. As shown, syringe interface/connector mechanism 4480includes a front plate 4482 that is similar in design to front plate4054 (shown in FIGS. 56 and 57). Front plate 4482 includes anindentation 4484 in a rear surface thereof that is sized to accommodateflex ring 4486. Front plate 4482 has a hole 4488 therethrough. It alsohas notches 4490 that accommodate posts 4492 on flex ring 4486.

[0380] Flex ring 4486 is shaped similarly to flex ring 4026. As shown,flex ring 4486 has two separate arcuate pieces 4494, 4496 that areconnected together along seams 4498, 4500 on either side. Two springs4502, 4504 are located on either side of flex ring 4486 to bias flexring 4486 into a relaxed position around syringe 4012 once insertedtherethrough.

[0381] A rotating ring 4506 is positioned behind flex ring 4486.Rotating ring 4506 has a hole 4508 therethrough and is provided with anumber of grooves 4510 in its inner surface. Rotating ring 4506 is notconnected directly to flex ring 4486 (as with other embodiments).Instead, rotating ring 4506 includes two posts 4512, 4514 that extendfrom a rear surface through rear plate 4516. As with other embodiments,rotating ring 4506 is positioned within an indentation (not shown) onthe inner surface of rear plate 4516.

[0382] Two semicircular arms 4518, 4520 are positioned behind rear plate4516. Each arm includes a post 4522, 4524 that engages posts 4492 onflex ring 4486. Each arm also includes a notch 4526, 4528 that engages apost 4512, 4514 on rotating ring, respectively.

[0383] The operation of release/connector mechanism 4480 is essentiallythe same as with previous embodiments. When syringe 4012 is insertedthrough flex ring 4486, the two segments 4494, 4496 of flex ring 4486spring apart into a tensioned state until ridge 4044 on syringe 4012clears the rear edge of the segments 4494, 4496 of flex ring 4486. Whenridge 4044 clears flex ring 4486, springs 4502, 4504 return to a relaxedstate and draw segments 4494, 4496 into engagement with syringe 4012.When segments 4494, 4496 return to a relaxed state, they preferablyprovide an audible “click”.

[0384] To remove syringe 4012 from release/connector mechanism 4480,syringe 4012 is rotated approximately one-quarter turn. As before,syringe 4012 is provided with projections 4050 that engage grooves 4510on the interior surface of rotating ring 4506. As rotating ring 4506 isturned, arms 4518, 4520 move outwardly from a relaxed position to atensioned position and apply pressure to posts 4492 to urge segments4494, 4496 of flex ring 4486 apart. Once the syringe is rotated asufficient distance, segments 4494, 4496 are sufficiently separated fromone another to release syringe 4012, preferably with an audible “click”.

[0385]FIGS. 121 and 122 illustrate one further example of arelease/connector mechanism 4550 according to the teachings of thepresent invention. Here, instead of providing a flex ring, four segments4552, 4554, 4556, 4558 are provided around the periphery of the commonhole 4560 through connector mechanism 4550. The four segments 4552-4558may be biased by any suitable mechanism. For example, segments 4552-4558may be connected to a rotating ring by arms in a similar manner asconnector mechanism 4480.

[0386] In addition, a front-loading syringe 4612 incorporating syringeencoding is shown in FIG. 126. Syringe 4612 includes a cylindrical body4630 with a tapering conical portion 4632 at a front end 4634. Conicalportion 4632 is integrally connected to a discharge end 4636.

[0387] At rear end 4622, syringe 4612 includes two encoding rings 4641,a flange 4642 (which, when syringe 4612 is connected to releasemechanism 4010, helps to prevent contrast medium that may leak from, forexample, discharge end 4636 from entering release/connector mechanism4010), an attachment ridge 4644, and preferably two or more, extendingrelease tabs or projections 4650. The rings 4641 preferably extendaround the circumference of syringe 4612, but the rings 4641 may besegmented if desired. Also, while two rings 4641 are shown, one, threeor more rings 4641 may be provided on syringe 4612 to accommodatevarying encoding requirements. The structure and function of theencoding system is described in U.S. application Ser. No. 09/765,498,filed on Jan. 18, 2001, and assigned to the Assignee of the presentapplication, the contents of which are hereby incorporated by reference.

[0388] The present invention also provides injectors and injectorsystems having certain “automated” or “auto” features that facilitatethe operation thereof. For example, the injectors and injector systemsof the present invention may be provided with one or more of thefollowing functions: “auto advance,” “auto engage,” “auto fill,” “autoprime” and “auto retract.” Each of these functions, together with theirattendant advantages and benefits, is described below in more detail inconjunction with empty, preloaded and/or prefilled syringes. As known inthe art, “empty” syringes are syringes that do not contain fluid whenmounted on an injector for an injection procedure. Empty syringestypically come in two forms: “plunger-rearward” syringes and“plunger-forward” syringes. Plunger-rearward syringes are syringeshaving plungers that are initially located at the rearward or proximalends thereof. Plunger-forward syringes are syringes having plungers thatare initially located at the forward or distal ends thereof. “Preloaded”syringes are empty syringes that have been filled with fluid (e.g., byhand or by use of an injector to aspirate fluid into the syringe) priorto an injection procedure, and then stored for subsequent use on aninjector for the injection procedure. “Prefilled” syringes are syringesthat have been filled with fluid prior to delivery to the customer.

[0389] In a preferred embodiment, the injectors and injector systems ofthe present invention are adapted to automatically identify, forexample, the types, sizes, fluid contents (if applicable) andconfigurations of syringes mounted thereon. Suitable sensors andencoding devices are discussed above and in U.S. Pat. No. 5,383,858 andPCT Publication No. WO 99/65548 (both of which are incorporated hereinby reference) to differentiate between varying syringes (e.g., empty,preloaded or prefilled syringes) used on injectors. These sensingschemes, or suitable alternatives as known in the art, could also beused to implement the auto features discussed below.

[0390] The “auto engage” feature allows an injector to automaticallyadvance the drive piston thereof to engage a syringe plunger uponinstallation or attachment of the syringe to the injector. In apreferred embodiment, the auto engage feature occurs without operatorintervention. This feature is particularly useful for preloaded andprefilled syringes, which typically have plungers located at someposition within the syringe barrel other than at the proximal and distalends thereof, and plunger-forward syringes. In the case of prefilledsyringes, the auto engage feature automatically connects the injectorpiston and syringe plunger for subsequent priming of the syringe (andassociated tubing) and subsequent injection. For plunger-forwardsyringes, the auto engage feature engages the piston and plunger forsubsequent retraction of the plunger for aspiration of fluid, such ascontract media, into the syringe.

[0391] The “auto advance” feature is related to, and may be considered atype or subset of, the auto engage feature. The auto advance featureallows an injector to automatically advance the plunger of a plungerrearward syringe (i.e., by the drive piston of the injector) to thedistal end of the syringe after the syringe is installed on theinjector. This feature operates to expel air from an empty,plunger-rearward syringe and to place the syringe plunger in a positionto be subsequently retracted to aspirate fluid, such as contrast media,into the syringe for an injection procedure. In a preferred embodiment,the injector senses the mounting or installation of the syringe thereonand automatically advances the piston without operator intervention todrive the plunger to the distal end of the syringe. Of course, thisfeature would ordinarily be used only with empty syringes (as comparedto preloaded or prefilled syringes) to prevent fluid from being expelledtherefrom.

[0392] As discussed above, in a preferred embodiment, the injectors andinjector systems of the present invention may be adapted toautomatically differentiate between, for example, empty syringes andpreloaded syringes. Because preloaded syringes are empty syringes thathave been filled with fluid and stored prior to an injection procedure,and further because operators, depending on the application or need, mayor may not preload empty syringes with fluid for storage prior to theinjection procedure, the injector may have difficulty differentiatingbetween empty, plunger-rearward syringes and preloaded syringes.

[0393] One possible arrangement to address this concern is to assemblethe plunger-rearward syringes with their plungers located at positionsrearward of the maximum fill volume of the syringes. As can beappreciated, this arrangement will result in preloaded syringes havingtheir plungers located (after loading with fluid) at some position equalto or forward of the maximum fill volume of the syringes. In operation,after a syringe is placed on the injector and identified as an emptysyringe, the auto engage feature will drive the piston forward to engagethe syringe plunger. If the piston engages the syringe plunger at aposition rearward of the maximum fill volume of the syringe, theinjector will discern that a plunger-rearward syringe has been installedthereon and the auto advance feature will be enabled to drive theplunger to the distal end of the syringe to expel air therefrom and toplace the plunger in position for aspiration of fluid into the syringe.On the other hand, if the piston engages the syringe plunger at aposition equal to or forward of the maximum fill volume of the syringe,the injector will discern that a preloaded syringe has been installedthereon. Of course, when the injector determines that a preloadedsyringe has been installed thereon, the auto advance feature will not beenabled (i.e., to prevent the piston from advancing the plunger to thedistal end of the syringe, thereby expelling the preloaded fluid formthe syringe).

[0394] The “auto fill” or “auto load” feature allows an injector toautomatically retract a syringe plunger (i.e., by means of the injectorpiston) to draw in or aspirate a programmed amount of fluid, such ascontrast media, into the syringe. Preferably, the auto fill featureoccurs without operator intervention, thereby allowing the operator toperform other tasks (e.g., programming the scanner or injector,positioning the patient on the scanner table, catherizing the patient)while the syringe is being filled with fluid. Of course, this featuretypically is not necessary for prefilled or preloaded syringes, whichalready contain fluid therein.

[0395] In a preferred embodiment, the auto fill feature also includes a“trapped air reduction” feature to reduce the amount of air aspiratedinto the syringe during the fluid aspiration procedure. During anaspiration procedure facilitated by, for example, the auto fill feature,the injector piston retracts the syringe plunger to draw fluid into thesyringe. Often, for example, when the aspiration flow rate issufficiently great, air is aspirated into the syringe along with thefluid. To reduce the amount of air aspirated into the syringe, thetrapped air reduction feature reverses the motion of the injector piston(i.e., to slightly advance the injector piston) one or more times duringthe aspiration procedure. By reducing the amount of air aspirated intothe syringe during the fill operation, the quantity and size of airbubbles formed in the syringe, as well as the time required tosubsequently expel air from the syringe and connecting tube (i.e.,priming the system) are reduced, resulting in a lower probability of aninadvertent air injection.

[0396] The “auto prime” feature allows an injector to automaticallyprime the fluid path (i.e., syringe and connecting tubing) before aninjection procedure. Preferably, the volume of fluid contained within aconnector tubing used with a syringe is pre-programmed into theinjector. For example, a 60′ low pressure connecting tubing (“LPCT”)provided by Medrad, Inc., the Assignee of the present application, foruse with its disposable syringes typically holds approximately 2.78 mlof fluid. Alternately, the operator may manually program the fluidvolume contained within the connector tube into the injector.

[0397] As will become apparent, the auto prime feature may befunctionally dependent, in certain respects, on the auto fill featuredescribed above. When a syringe is filled with fluid (i.e., by means ofthe auto fill feature), the injector automatically compensates for theconnector tube by adding its corresponding fluid volume to the fluidvolume desired by the operator to be aspirated into the syringe for aninjection operation. For example, if the operator desires to fill thesyringe with 150 ml of fluid for an injection procedure, the auto fillfeature will compensate for the connector tube fluid volume byautomatically adding 2.78 ml of fluid (e.g., for a 60′ LPCT), for atotal volume of 152.78 ml aspirated into the syringe. After the syringeis filed with fluid, the auto prime feature would then cause theinjector piston to advance the syringe plunger to the extent necessaryto expel air from the syringe and connector tube system, preferablywithout prompting by the operator. Once the auto prime function isconducted, fluid should be present at the patient end of the connectortube (i.e., the end that is connected to the catheter).

[0398] As can be appreciated, the auto prime feature may save operatortime and reduce the amount of wasted fluid. By automaticallycompensating for the fluid contained within the connector tube, theoperator does not have to vigilantly watch the progression of the fluidfrom the syringe through the connecting tube in order to stop theadvancement of the piston before a significant amount of fluid isdischarged from the end of the connector tubing. Also, because someoperators of conventional injectors advance the piston quickly to lessenthe time required to prime the syringe and tubing system, often asignificant amount of fluid will be expelled from the end of theconnector tubing before the operator stops the piston's advancement. Ifa sufficient amount of contrast is expelled, the syringe may have to bere-filled (and the syringe and tubing system subsequently re-primed) toinsure that it contains a sufficient amount of fluid for the requiredinjection procedure.

[0399] While the auto prime feature is preferably intended for use withempty syringes that have been filled with fluid by an aspirationprocedure on the injector (i.e., non-prefilled and non-preloadedsyringes), the auto prime feature could also be used with prefilled andpreloaded syringes.

[0400] The “auto retract” feature allows an injector to automaticallyretract the injector piston after a syringe is removed or disconnectedfrom the injector. At the end of an injection procedure, the injectorpiston and the syringe plunger is typically located at the distal end ofthe syringe. Therefore, as described above and in U.S. Pat. Nos.5,383,858 and 5,300,031 (both of which are incorporated herein byreference), after the syringe is disconnected from the injector, theinjector piston often extends from the front of the injector (or withina pressure jacket attached to the front of the injector). Especially inthe case of plunger-rearward syringes, preloaded syringes and prefilledsyringes, the piston usually must be retracted in order to mount a newsyringe onto the injector for the next injection procedure. To saveoperator time in retracting the piston, the auto retract featureautomatically retracts the piston after the injector senses that thesyringe has been removed therefrom (e.g., after an injection procedure)to place the injector piston in position to accept a new syringe. Ifplunger-forward syringes are being used on the injector, the autoretract feature may be deactivated to prevent unnecessary and/orredundant piston movements. The auto retract feature could be manuallydeactivated by the operator or automatically by the injector. Forexample, when a plunger-forward syringe is installed on and identifiedby the injector, the injector could automatically initiate a defaultsetting to deactivate the auto retract feature for subsequent syringesuntil an operator override is activated or until the system detects theattachment of a prefilled, preloaded or plunger-rearward syringe. Whenthe injector detects a prefilled or preloaded syringe, the system cancompensate for any residual air remaining in the syringe by adjustingthe amount of priming to be conducted. For example, if the prefilledsyringe typically contains approximately 1.2 ml of air or “dead space”and is connected to a 60′ LPCT (accommodating approximately 2.78 ml offluid), the injector system would prime approximately 3.97 ml from thesyringe and connecting tube system.

[0401] As will be appreciated, depending on operator need, the autofeatures described above could be used independently or in conjunctionwith one another to facilitate injector use. For example, the autofeatures described above could be used with a plunger rearward syringein the following manner. After an operator installs the plunger rearwardsyringe on an injector, the auto advance feature advances the syringeplunger to the distal end of the syringe (i.e., to expel air from thesyringe and to place the plunger into position to aspirate fluidthereinto). The auto fill feature subsequently aspirates a predeterminedamount of fluid into the syringe, based on the desired operator amountfor the injection procedure and, preferably, compensating for the fluidvolume of the connector tubing. The auto prime feature thenautomatically advances the injector piston and syringe plunger to removeair from the syringe and connecting tube system. Subsequently, after theinjection procedure is completed and the syringe is removed from theinjector, the auto retract feature retracts the injector piston to placethe injector in position for the next injection procedure with a plungerrearward syringe, a preloaded syringe or a prefilled syringe.

[0402] As another example, the auto features could be used with aprefilled syringe or a preloaded syringe in the following manner. Afteran operator places the prefilled syringe or preloaded syringe on theinjector, the auto engage feature advances the injector piston into thesyringe to mate or engage with the syringe plunger. The auto primefeature then advances the piston and plunger to expel air from andthereby prime the syringe and connector tubing system. Subsequently,after the injection procedure is completed and the syringe is removedfrom the injector, the auto retract feature retracts the injector pistonto place the injector in position for the next injection procedure witha plunger rearward syringe, a preloaded syringe or a prefilled syringe.

[0403] As yet another example, the auto features could be used with aplunger forward syringe in the following manner. After an operatorplaces the plunger forward syringe on the injector, the auto engagefeature advances the injector piston into the syringe to mate or engagewith the syringe plunger. The auto fill feature subsequently aspirates apredetermined amount of fluid into the syringe, based on the desiredoperator amount for the injection procedure and, preferably,compensating for the fluid volume of the connector tubing. The autoprime feature then automatically advances the injector piston andsyringe plunger to remove air from the syringe and connecting tubesystem. Subsequently, after the injection procedure is completed and thesyringe is removed from the injector, the auto retract feature retractsthe injector piston (if, for example, the default setting to deactivatethe auto retract feature for plunger forward syringes has beenoverridden by the operator) to place the injector in position for thenext injection procedure with a plunger rearward syringe, a preloadedsyringe or a prefilled syringe. If new plunger forward syringes are tobe used with the injector (and the default setting to deactivate theauto retract feature for plunger forward syringes has not beenoverridden by the operator), then the auto retract feature will notoperate and the piston is left in its extended position for the nextsyringe.

[0404] The injectors and injector systems of the present invention mayalso include additional features complementary to one or more of theauto features described above to further enhance the usefulness of theauto features and to free operators to perform additional functions. Forexample, the injectors and injector systems of the present invention maybe provided with an attachment device for holding fluid sources, such asbottles or bags, during the auto fill function. By holding the fluidsource during the auto fill function, the need for the operator to holdthe fluid source during filling of the syringe is eliminated, therebyfreeing the operator for other activities preparatory to the injectionprocedure. Of course, the fluid source attachment device would providebenefit to the operator apart from the auto fill function. For example,if the auto fill feature is not available on a particular injector, thefluid source attachment device would still function to hold the fluidsource during operator-enabled filling operations.

[0405] In addition, the injectors, syringes and injectors systems of thepresent invention may be provided with an attachment device for holdingthe patient end of the connector tubing during the priming function(e.g., auto prime or operator-enabled priming). By holding the patientend of the connector tubing, preferably in the vertical direction toprevent fluid from dripping out of the patient end, the connector tubingattachment device frees the operator for other activities preparatory tothe injection procedure. Of course, various other injector operations(injection protocol programming, check for air, etc.) are or may beconducted between the various auto functions.

[0406] The foregoing description and accompanying drawings set forth thepreferred embodiments of the invention at the present time. Variousmodifications, additions and alternative designs will, of course, becomeapparent to those skilled in the art in light of the foregoing teachingswithout departing from the scope of the disclosed invention. Forexample, the respective mating connection and release mechanisms on theinjectors and the syringes described above may be interchanged. Thescope of the invention is indicated by the following claims rather thanby the foregoing description. All changes and variations that comewithin the meaning and range of equivalency of the claims are to beembraced within their scope.

What is claimed is:
 1. A syringe for use with an injector comprising asyringe retaining mechanism, the syringe comprising: a body comprising arear end and a front end; a plunger movably disposed within the body; atleast one attachment member associated with the body, the at least oneattachment member adapted to releasably engage the syringe retainingmechanism of the injector regardless of the orientation of the syringewith respect to the injector; and an encoding device operable to providesyringe information to the injector.
 2. The syringe of claim 1 whereinthe at least one attachment member comprises an annular ridge disposedon the body.
 3. The syringe of claim 1, further comprising one or moreprojections associated with the body, the one or more projectionsadapted to engage corresponding members of the syringe retainingmechanism to enable release of the syringe from the injector throughrotational motion.
 4. The syringe of claim 1 wherein the at least oneattachment member comprises one or more tab members.
 5. The syringe ofclaim 4 wherein each of the tab members comprises a first tab endattached to the body and a second tab end adapted to engage the syringeretaining mechanism of the injector.
 6. The syringe of claim 4 whereinthe tab members are resilient members.
 7. The syringe of claim 4 whereinthe tab members are integrally formed with the body.
 8. The syringe ofclaim 1, further comprising a flange associated with the body andadapted to engage a corresponding surface of the injector when thesyringe is releasably engaged therewith.
 9. The syringe of claim 8wherein the flange is adapted to substantially prevent fluid fromentering the interior of the injector.
 10. The syringe of claim 1wherein the at least one attachment member is moved in an axialdirection to releasably engage the injector.
 11. The syringe of claim 1wherein the at least one attachment member is moved in a verticaldirection to releasably engage the injector.
 12. The syringe of claim 1wherein the at least one attachment member is associated with the rearend of the body.
 13. The syringe of claim 1 wherein the at least oneattachment member is associated with the front end of the body.
 14. Asyringe for use with an injector comprising a syringe retainingmechanism, the syringe comprising: a body comprising a rearward end anda forward end; a plunger movably disposed within the body; at least oneattachment member associated with the body; and at least one rotationmember comprising a recess formed in the body for releasably engaging acorresponding member of the syringe retaining mechanism of the injector.